Update Readme.md with code styling.

Added code formatting for Linux commands for building.
Change file case, added some wstring casts
Added LIBS := -ldl to Makefile
fr: fix build error, use string instead of char
Merge pull request #12 from waywardgeek/master

Changed more file cases, and fixes to compile with wxgtk 3.0
Merge pull request #8 from pmalek/patch-1

Update Readme.md with code styling.