Bug 890784 (part 1) - Create a new vm/Runtime module and put JSRuntime in it.  r=wmccloskey.

--HG--
rename : js/src/jscntxtinlines.h => js/src/vm/Runtime-inl.h
rename : js/src/jscntxt.cpp => js/src/vm/Runtime.cpp
rename : js/src/jscntxt.h => js/src/vm/Runtime.h
Bug 890784 (part 2) - Fix up #includes after the creation of the vm/Runtime module.  r=wmccloskey.
Bug 890595 - Find next/prev/highlight buttons should be enabled if there's an initial string present. r=gavin