Wrapping and finding template functions

[technosophos]

Per #25, implement the Sprig functions for Bartholomew. Rather than file an issue for each function, I figured I'd break these down into small batches. (Note: I am not entirely sure all of the functions can be done with the same syntax. I am no pro in writing the Handlebars functions.)

• wrap COUNT STRING Wrap text at a particular length (line ending: \n)
• wrap_with COUNT ENDING STRING Wrap STRING using ENDING as the line ending. e.g. wrap_with "<br>" some_text will use <br> instead of a line break
• contains SUBSTRING STRING returns boolean true if SUBSTRING is contained within STRING
• has_prefix PREFIX STRING returns boolean true if PREFIX is found at the beginning of STRING
• has_suffix SUFFIX STRING returns boolean true if SUFFIX is found at the end of STRING
• cat STRING... Concatenates the given strings with spaces in between. cat "hello" "world" becomes hello world
• indent COUNT STRING indent the string COUNT characters
• nindent COUNT STRING add a new line and indent the string COUNT characters, (might not need this... it was originally really for YAML formatting)
• replace TARGET REPLACEMENT STRING Replace all instances of TARGET with REPLACEMENT in the STRING
• shuffle STRING randomly reorder the characters in STRING