Turn off deprecation warnings for fields and values that can be easily translated.

To ease the transition to 5.0, allow these values to continue to work while marking them deprecated in the documentation. Will put the messages back some time after release when folks have had a chance to switch.

--HG--
branch : feature/edit-continue-switch
Add new editAndContinue() API to replace NoEditAndContinue flag

Make it easier and more intuitive to support platforms/toolsets where edit-and-continue is available but turned off by default. Can now turn off with editAndContinue("off") instead of flags("NoEditAndContinue"), and turn it on with editAndContinue("on") instead of removeflags("NoEditAndContinue").

The NoEditAndContinue flag is still in place, and continues to behave as it did before, but will be marked deprecated in the documentation.

--HG--
branch : feature/edit-continue-switch
Correctly report syntax errors in loaded scripts

Syntax errors were getting reported as "file not found" errors instead. Correctly pass through the right error code and message.

--HG--
extra : rebase_source : 2275959aff5e9f276d6e4eee59e83e035a0dba77