Compile with bumped rct.
Bump rct
Don't return 0 if we didn't find a compiler.
Some minor updates to the README
Use file-truename for all buffer-file-name calls
Build compilation database
Add a --get-compile flag for getting the command line for a file

This is an attempt to make it easier to use other tools, many of
which can use either a compilation database or the full command
line.
Hook in next-error, etc., to make iterating through matches more convenient