Closes #12 : all calls to cmdarg_usage go to stderr
Close #7 : use BASH_VERSINFO instead of janky version check
Clarify #14 : boolean processing places optarg into cmdarg_argv, we can debate that later
Close #11 : This does, indeed, fix the big janky naming bug
Made validators less silly (require strict functions) and updated docs
Close #13 : cmdarg_helpers[] introduced, README documentation updated
Added UPGRADING.md for 2.0 breaking changes
Update UPGRADING.md
Close #17 and Close #16

Introduces CMDARG_ERROR_BEHAVIOR. Adds some more tests. Introduces new
behavior for hash validators (see README). Fixes a few odds and ends.
Close #5 : Removed all calls to cut/grep
Close #9 : Ensured all local vars are declared local. Also removed builtin cmdarg_cfg['cfgfile'] loading as it was undocumented and even I forgot it was there.
Fixes #6 : Proper array bounds checking
Fixed some broken longopt and helpers related tests