Allow fine-grained control over JavaScript compiler options via *.ini

JavaScriptOptions bit-field can be set in sbbs.ini and jsexec.ini to over-ride the default JS compiler options which have been changed from 0 to (options previously only used by JSDoor):
JIT | METHODJIT | COMPILE_N_GO | PROFILING

* JIT - TraceMonkey
* METHODJIT - JägerMonkey
* COMPILE_N_GO - compile-time scope chain resolution of consts
* PROFILING - Choose between TraceMonkey and JägerMonkey at compile-time based on profiling results

Other options available but not enabled by default:
* STRICT - warn on debious practice (i.e. similar to "use strict")
* WERROR - convert warnings to errors
* VAROBJFIX -  use last object on scope chain as the ECMA 'variables object'
* RELIMIT - Throw exception on any regular expression which backtracks more than n^3 times, where n is length of the input string
* ANONFUNFIX - Disallow function () {} in statement context per ECMA-262 Edition 3.
* METHODJIT_ALWAYS - Always whole-method JIT, don't tune at run-time.

Also:
- Fixed JS warning string formatting (missing space separator).
- Removed an extraneous new-line in lprintf() call in mailsrvr.
- Added basic assertEq() global method to jsexec, required when running SpiderMonkey test scripts.