restore the ll[io]fstream because we need them as wrappers on Windows for wide char paths; on other platforms they are now just typedefs to the std classes

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.

LLControlGroup::declareControl(), declareString() etc. etc. all used to return
BOOL -- which no one ever examines because it unconditionally returned TRUE.
Make it return the (possibly new) LLControlVariable* instead.

DEV-50166 - LLBasicCertificateChain::validate calls in log
Added caching of certificates that have been validated.
The sha1 hash for the certificate is stored and is associated
with the from and to times.  When the certificate is validated,
the code determines whether the certificate has successfully
been validated before by looking for it in the cache, and then
checks the date of the cert.  If that is successful,
the validation calls with success.

Otherwise, it proceeds to do a full validation of the certificate.

CR: Karina

certificate notification code
-r 118191

ignore-dead-branch

secapi stuff as well as certificate handling stuff.
Grid manager as well