Merge pull request #2785 from bovi/install-doc

Remove INSTALL and improve README instead

INSTALL

-* Prerequisites
-
-  1. Make sure you have bison (http://www.gnu.org/software/bison/) installed in
-     your system.
-  2. Make sure you have ruby installed in your system (required to build).
-
-
-* Compilation and Installation
-
-  1. Run make in the top directory.
-
-     This command will create a build directory with a directory for the host
-     environment and one for each crossbuild environment based on the settings
-     in the build_config.rb file.
-
-     Assuming a default build, each of the environment directories will have
-     the following important directories:
-
-       * bin - The binary executables for this environment
-       * lib - The libraries for this environment
-
-     You can find the header files in the include directory at the root of the
-     project.
-
-     You can directly invoke 'minirake' with the following command:
-
-         $ ruby ./minirake
-
-If an error occurs when compiling mruby, it will be helpful for others if you
-send a detailed report to the developers that includes the error log, machine,
-and OS type.
-
-
-* Adding existing gems
-
-Gems from the [list of mruby gems](http://www.mruby.org/libraries/) can be
-added by adding their respective GitHub URLs to build_config.rb. For example,
-to add implementations of the File and IO Ruby core classes to mruby, insert
-the following in build_config.rb under the comment section `Use mrbgems`:
-
-    conf.gem :git => 'git@github.com:iij/mruby-io.git', :branch => 'master'
-
-Afterwards, re-run:
-
-    ruby ./minirake
-
-
-* Porting to other platforms
-
-That's all.
-

README.md

@@ -46,7 +46,7 @@ We don't have mailing list, use GitHub forum <http://github.com/mruby/mruby>.
 
 ## How to compile and install (mruby and gems)
 
-See the INSTALL file.
+See the *doc/compile/README.md* file.
 
 
 ## Running Tests
@@ -60,11 +60,12 @@ Or
     $ ruby ./minirake test
 
 
-## Customization
+## How to customize mruby (mrbgems)
 
 mruby contains a package manager called *mrbgems*. To create extensions
-in C and/or Ruby you should create a *GEM*. You will find a complete
-documentation with examples under *examples/mrbgems*.
+in C and/or Ruby you should create a *GEM*. For a documentation of how to
+use mrbgems consult the file *doc/mrbgems/README.md*. For example code of
+how to use mrbgems look into the folder *examples/mrbgems/*.
 
 
 ## License