rm unused CLI opts
linux binary links
installation instructions on homepage
fix check for exec.ErrNotFound
more informative err msg
remove python from the docs homepage temporarily
Added additional instructions for beginning emacs users, as recommended by @pathouse
use BSD-compatible "find"
Clean filepaths used to look up refs in the `src api` methods

This fixes an issue reported by Shiva where Ruby sources units whose
files are listed as ./file1, ./file2 (instead of just file1 and file2)
would not be matched when using `src api` methods.
Don't require rvm for Ruby toolchain in `src toolchain install-std`
src describe now returns an absolute path.
add SourceUnit() method on make rules (to satisfy implicit interface)
sourcelib -> srclib