BUG-3605 / CHUIBUG-197 Don't create excessive amounts of string objects in LLNormalTextSegment::getNumChars.

The logic in llcommandlineparser.cpp's setControlValueCB() callback function
for converting command-line switch argument values from string to the actual
type of the map-to settings variable had a couple special cases for boolean
and LLSD array. But for S32, U32 and F32, it simply used default LLSD
string-to-numeric conversion. LLSD's string-to-numeric conversion is a bit
lame: for non-numeric strings, it shrugs and returns 0.
Introduce onevalue() and badvalue() helper functions that, like certain errors
during command-line parsing, throw LLCLPError. Use them to streamline certain
redundancies in setControlValueCB(). Introduce convertTo<T>() helper function
that uses boost::lexical_cast() for slightly more stringent conversions. Add
cases for U32, S32 and F32 targets.
setControlValueCB() is actually called only by LLControlGroupCLP::notify(),
not during actual command-line parsing.
Make LLControlGroupCLP::notify() return bool. Make it catch LLCLPError, set
the error for getErrorMessage() and return false on that exception.
Package LLAppViewer::initConfiguration()'s response to initParseCommandLine()
returning false as a new handleCommandLineError() function; invoke it both
there and when LLControlGroupCLP::notify() returns false.

Previous CHOP-959 logic set a flag to remember that settings variable
RenderQualityPerformance was set (by --graphicslevel), so it could be applied
once LLViewerWindow is constructed. But on first viewer run, LLViewerWindow
constructor calls LLFeatureManager::applyRecommendedSettings(), which resets
that settings variable! So don't just set a flag, actually capture the
requested RenderQualityPerformance value for later.

missing code block from previous change as per Dave P's advice

bullet-proof.  Reviewed by Kelly

MAINT-2939 FIXED [CHUI] On Windows machine location address bar in viewer goes blank if location is selected and a menu item is seleted

viewer_manifest.py uses its base-class llmanifest.LLManifest.put_in_file()
method to create several different files in the install image being
marshalled. I based the logic to create settings_install.xml on that example.
Unfortunately I failed to notice that after every existing call, the script
also explicitly appended the newly-created file to self.file_list... which
only matters on Windows. file_list is fed to the NSIS installer.
Change put_in_file() method to implicitly append to self.file_list.
Change every existing viewer_manifest.py call to pass new put_in_file(src=)
param instead of explicitly appending to self.file_list.

The comment advises grepping for "Global" rather than specifically pointing to
llcontrol.cpp because that's NOT the only place that relies on the name
"Global"! Besides, by the time someone does want to change the name, still
other such dependencies could've crept in.

Initial change made LLControlVariable::mPersist an enum, but retained
bool/BOOL public API. setPersist(true) set one value, setPersist(false) set
another, forcePersist() set the third. Per code review, expose enum to public,
make setPersist() (and LLControlVariable constructor, and LLControlGroup::
declareControl(), and all the LLControlGroup::declareMumble() methods, and all
the unit-test dummy declareMumble() method bodies) accept that enum. Remove
forcePersist(). Fix calls to LLControlGroup::declareMumble() accordingly.
Also rename PERSIST_YES to PERSIST_NONDFT, also per code review.

added default sourceid and check that sourceid is not blank, hoping to get the windows builds to recognize the value