hgmerge: fix diff+patch detection; cleanups
Details:
- actually show help message when no tools are found
- whitespace cleanup (stupid emacs)
- quote more variables
- simplify merge/diff3 error handling
adding fooadding bombadding a.cadding dir/a.oadding dir/b.o! a.c! dir/a.o! dir/b.o? .hgignorea.c: unsupported file type (type is fifo)! a.c