Several improvements and bug fixes, new "_.deepPluck" callback methods

• UMD support #23, by @spenceralger
• Faster and better parsing of string based propertyPaths #24, by @spenceralger
• _.deepPluck and _.deepHas now work with string properties #25, by @beaugunderson
• New "_.deepPluck" callback methods
  • _.deepFindIndex
  • _.deepFindLastIndex
  • _.deepFirst
  • _.deepFlatten
  • _.deepInitial
  • _.deepLast
  • _.deepLastIndexOf
  • _.deepRemove
  • _.deepRest
  • _.deepSortedIndex
  • _.deepUniq
  • _.deepCountBy
  • _.deepEvery
  • _.deepFilter
  • _.deepFind
  • _.deepGroupBy
  • _.deepIndexBy
  • _.deepMax
  • _.deepMin
  • _.deepReject
  • _.deepSome
  • _.deepSortBy
  • _.deepFindKey
  • _.deepFindLastKey