implement new style tinting: pre-color hsl adjustment to preserve hue/sat ranges
clamp hsl values
Pass-thru on upgrade attempts of new-style tintstrings.
Upgrade should use 0 as first value in alpha range.
fix flow error as return is unreachable (clang++ -Wunreachable-code)
mark standalone functions static
cleanup unused code
remove uneeded semicolons
remove uneeded semicolons
static decl and correct float comparision
Add missing test file
update tinting test images as new results with advanced hsl method seem reasonable
use signed type for blending - fixes potential overflow - refs #27
Merge pull request #28 from developmentseed/hsl

Full HSL support for tinting