Improve inspector reliability.

- Refactor regex-related operations to avoid substitution of
  special characters in cases where they should be left alone.
- Improve filtering of duplicate/substring matches of localized strings.
- Remove attempts at matching localized string arguments.  Intermediate
  forms of this patch fixed infinite recursion issues, but logging
  indicated exponential algorithmic behavior even with valueTooGeneric
  still in place.  Note that the recursive matching code only ever
  existed in a skeleton form that logged warnings, but did no actual
  work.
- Remove valueTooGeneric, as it wasn't generic enough to filter all the
  possible too-generic format strings.
Improve inspector's localization support.

- Substantially expand the list of known localization codes.
- Present localized strings in a stable order (alphabetized by
  localization code).
Make shutdown cleanup more robust.

- Modify IOSServer to use two-stage initialization so that a shutdown
  handler is always registered before internal state is initialized.
- Close all open sessions.
- Add a missing shutdown handler registration in
  InstrumentsBackedNativeIOSDriver.
Fix inspector for iPhone/7.0 combination.

The iOS 7.0 SDK does not support non-retina iPhones, so if 7.0 is in use
default to using a 3.5-inch retina iPhone (and warn).

Add DeviceVariation values for 64-bit iPhone and iPad, and normalize
existing value names.
Miscellaneous cosmetic cleanup.