grc: remove "c" key shortcut for create heir action
modtool: Fixes for intial templates of a block.

1. adds '$' to args in the GRC xml <make> tag.
2. sets <+ITYPE+> and <+OTYPE+> for all I/O data types in io_signature and in work functions to be more clear what needs modification.

Conflicts:

	gr-utils/src/python/modtool/templates.py
Merge branch 'maint'