v2.2 - New command-line interface

This release completely redoes how VHDLproc is used from the command-line to help with interoperability between programs.

For instance, VHDLproc is now passed a series of input files, processes them, and then saves them to new files with a given extension, either in the same directory or a new one. It also prints the paths to the parsed files to stdout. This means for using with GHDL, it's as easy as:

vhdlproc *.vhdl 
ghdl -a --std=08 *.proc.vhdl
ghdl -r --std=08 testbench

or

vhdlproc *.vhdl -o build
ghdl -a --std=08 build/*.vhdl
ghdl -r --std=08 testbench

or even

ghdl -a --std=08 $(vhdlproc *.vhdl -o /tmp/vhdlproc/)
ghdl -r --std=08 testbench

This is unfortunately not backwards compatible with the old way of using VHDLproc.