Removed the litstr overloads of Array::rvalAt, rvalAtRef, lval,
lvalPtr, lvalAt, and set. The main one left to do is operator[].
Fixed a bug in f_get_html_translation_table() where we were copying
the null terminator of what should be a one-character string, thus
creating a two-character string with s[1] == 0. (cc @jdelong)
In class Extension, store a String for the name instead of
const char*. cc @sgolemon
This change is mostly for FB internal organizational reasons.
Building is not effected beyond the fact that the target now
lands in hphp/hhvm/hhvm rather than src/hhvm/hhvm.