Array&String toolbox enhancement

[Rratic]

Here's a set of things that need to be enhanced found while developing

• "find"-series functions for arrays (e.g. findfirst(0, [0]))
• more deleting function for vectors (delete indicated value, etc)
• string handle: splice; function to make a string end with exact amounts of /, etc
• enhance string replacing function

I'm using 1.8.3 and quite surprised many functions are still not in Base

ideas welcome!

[andrewjradcliffe]

• "find"-series: use predicates, e.g. curried predicates findfirst(==(0), [0])
• deleting functions: filter! with an appropriate predicate should meet the need. If value is known by index, then deleteat!