Add stripLeadingSlash to KiwiUrls

[sleberknight]

I needed to strip a leading slash from a URI the other day. I know, really difficult stuff. I assumed we had a method in KiwiUrls to do this simple task, but we only have a method to prepend a leading slash, and a method to strip a trailing slash.

I did the task using some methods in Apache Commons StringUtils and specifically the stripStart method, so StringUtils.stripStart("/some/random/path", "/") returns "some/random/path" as you expect. But, I also combined this with a check for null and blank strings, etc.

So, might as well have a dedicated method in KiwiUrls regardless of how simple it is. It should:

• not allow null values (let it throw a NPE like prependLeadingSlash)
• allow empty strings, returning empty in this case
• trim leading and trailing whitespace, so that " /some/random/path " results in "some/random/path"
• return the same value if there is no leading/trailing whitespace and no leading slash