Fix "Building KiCad from Source" developers documentation.

* Change command blocks from using ``` to delineate block and use indentation
  instead.  The ``` method seems to be broken on Doxygen 1.8.9.1 used by the
  autobuilder.  It also removes the line numbering which did not make sense
  for commands that spanned multiple lines.

Documentation/development/compiling.md

@@ -208,9 +208,8 @@ Github mirror: https://github.com/KiCad/kicad-source-mirror
 
 # Building KiCad on Linux # {#build_linux}
 
-To full KiCad build on Linux, do the following:
+To perfrom a full build on Linux, run the following commands:
 
-```
     cd kicad_source_tree
     mkdir -p build/release
     mkdir build/debug               # Optional for debug build.
@@ -222,7 +221,6 @@ cmake -DCMAKE_BUILD_TYPE=Release     \
           ../../
     make
     sudo make install
-```
 
 If the CMake configuration fails, determine the missing dependencies and install them on your
 system.  By default, CMake sets the install path on Linux to /usr/local.  Use the
@@ -247,14 +245,12 @@ The easiest way to build KiCad using the [MSYS2][] build environment is to use t
 development branch.  To build the KiCad package, run the `msys2_shell.bat` file located in the
 MSYS2 install path and run the following commands:
 
-```
     pacman -S git
     mkdir src
     cd src
     git clone https://github.com/Alexpux/MINGW-packages
     cd MinGW-packages/mingw-w64-kicad-git
     makepkg-mingw -is
-```
 
 This will download and install all of the build dependencies, clone the KiCad source mirror
 from Github, create both 32-bit and 64-bit KiCad packages depending on your MSYS setup, and
@@ -268,7 +264,6 @@ method of building KiCad, your task is significantly more involved.  For 64 bit
 the `mingw64_shell.bat` file located in the MSYS2 install path.  At the command prompt run the
 the following commands:
 
-```
     pacman -S mingw-w64-x86_64-cmake \
               mingw-w64-x86_64-doxygen \
               mingw-w64-x86_64-gcc \
@@ -297,7 +292,6 @@ cmake -DCMAKE_BUILD_TYPE=Release \
           -DKICAD_SCRIPTING_WXPYTHON=ON \
           ../../
     make install
-```
 
 # Building KiCad on OSX # {#build_osx}
 
@@ -307,7 +301,6 @@ building KiCad on OSX, see the [OSX bundle build scripts][].
 
 Download the wxPython source and build using the following commands:
 
-```
     cd path-to-wxwidgets-src
     patch -p0 < path-to-kicad-src/patches/wxwidgets-3.0.0_macosx.patch
     patch -p0 < path-to-kicad-src/wxwidgets-3.0.0_macosx_bug_15908.patch
@@ -335,11 +328,9 @@ export MAC_OS_X_VERSION_MIN_REQUIRED=10.7
         --enable-universal-binary=i386,x86_64 \
         CC=clang \
         CXX=clang++
-```
 
 Build KiCad using the following commands:
 
-```
     cd kicad-source
     mkdir -p build/release
     mkdir build/debug               # Optional for debug build.
@@ -358,7 +349,6 @@ cmake -DCMAKE_C_COMPILER=clang \
           ../../
     make
     make install
-```
 
 [download]: http://kicad-pcb.org/download/
 [KiCad website]: http://kicad-pcb.org/