basicfuncs-plus: Added padding template function.

Padding template function extends a string to a specified
width with prepending specified characters. The default
padding character is ' '(space).

For example:
$(padding $MESSAGE 10 X): bar -> XXXXXXXbar
$(padding $MESSAGE 10 foo): bar -> foofoofbar
README: Added basicfuncs functions
Merge pull request #43 from talien/f/padding-template-function

basicfuncs-plus: Added padding template function.
release: Preparations for 0.3.0