README: Add info on chaining and configuration

Author: LefterisJP

README.org

@@ -32,7 +32,7 @@ Regardless of where you installed solidity mode from, you need to require the pa
 
 ** Interface with linters
 *** Provide path to solc binary
-The ~solc~ binary is assumed to be part of the PATH. Wherever that is not the case you would have to manually
+The =solc= binary is assumed to be part of the PATH. Wherever that is not the case you would have to manually
 set the location of the binary like below:
 #+BEGIN_SRC emacs-lisp
 (setq solidity-solc-path "/home/lefteris/ew/cpp-ethereum/build/solc/solc")
@@ -41,7 +41,7 @@ set the location of the binary like below:
 Note: This better be set before requiring solidity mode.
 
 *** Provide path to solium binary
-The ~solium~ binary is assumed to be part of the user's ~PATH~. If this is not the case
+The =solium= binary is assumed to be part of the user's =PATH=. If this is not the case
 then set its location like below:
 #+BEGIN_SRC emacs-lisp
 (setq solidity-solium-path "/home/lefteris/.npm-global/bin/solium")
@@ -53,19 +53,24 @@ Solidity mode can also interface with [[https://github.com/flycheck/flycheck][fl
 download and install the flycheck package. Then configure it to either work on
 all modes or enable it only for solidity mode.
 
-Flycheck can interface either with solc or with [[http://solium.readthedocs.io/en/latest/][solium]]. Choose the appropriate
-linter to use by providing the following in your emacs init:
+Flycheck can interface with solc and/or with [[http://solium.readthedocs.io/en/latest/][solium]]. You have to specifically set the path
+to both executables and activate the checker integration by setting the following:
 
+To activate =solc= checker
 #+BEGIN_SRC emacs-lisp
-(setq solidity-flycheck-active-checker "solium")
+(setq solidity-flycheck-solc-checker-active t)
+#+END_SRC
+
+To activate =solium= checker
+#+BEGIN_SRC emacs-lisp
+(setq solidity-flycheck-solium-checker-active t)
 #+END_SRC
 
-If you want to use ~"solc"~ replace ~"solium"~ with it.
 
 Keep in mind that you need to provide the path to either solc or solium unless
-emacs can already find it in your environment's ~PATH~. Even if you can call it
+emacs can already find it in your environment's =PATH=. Even if you can call it
 from the command line it does not mean that EMACS can see it as emacs may be started
-by systemd at which point ~PATH~ is not fully populated.
+by systemd at which point =PATH= is not fully populated.
 
 *** Configuring solc checker
 
@@ -82,13 +87,19 @@ By default this is false. If you want to include the standard contracts just add
 You can configure flycheck's solium incocation with the following arguments
 
 **** solium RC file
-By default solium looks at the current directory of the file you are editing in order to find ~.soliumrc.json~. Having this
+By default solium looks at the current directory of the file you are editing in order to find =.soliumrc.json=. Having this
 file is required. But you can point to an external configuration file by putting the following anywhere in your emacs init file.
 
 #+BEGIN_SRC emacs-lisp
 (setq flycheck-solidity-solium-soliumrcfile "/home/path/to/common/.soliumrc.json")
 #+END_SRC
 
+*** Chaining both checkers
+If you enable both checkers then their results are chained. The variable =solidity-flycheck-chaining-error-level= controls
+how they are chained. Its value can be either =t=, =error=, =warning= or =info= and that controls the maximum error level
+of the solc checker after which solium will not run. If =t= is given solium will always run. The default is =warning=, so
+if anything over than a warning is found in solc solium will not run.
+
 * Features
 + Syntax highlighting
 + Indentation