Merge pull request #63 from blocktrail/nestedmux

accept a callable function to `Mux::mount()` which can build a child mux
added failing tests for mounting a static route on a pcre mount
support pattern in ->mount with static ->add properly.
added test for mounting with a callable
added failing test for options not being merged correctly
using array_replace to fix options not bieng merged nicely
bump to rerun test
fixed ext test
Merge branch 'merging-options'

Conflicts:
	src/Pux/Mux.php
	test/Pux/MuxMountTest.php
Merge branch 'nestedmux'

Conflicts:
	test/Pux/MuxMountTest.php