pulled swap() out of ui time block
cleaned up internal lltrace dependencies, factored out common accumulator definitions

scene monitor output is cleaned up, no duplicate first frame, less scientific notation
periodic recording extension now works more cleanly

renamed llstatic_assert_template to LL_BAD_TEMPLATE_INSTANTIATION

moved collapsed flag to fast timer tree node

Automated merge with bundle:d:\code\viewer-interesting+c:\users\richard\appdata\local\temp\thg.7jrj8n\https__bitbucket.org_lindenlab_viewer-interesting_jch9cd.hg

removed implicit flushes on reads from recorders for better performance
made sure stack timers were updated on recorder deactivate
faster rendering and better ui for fast timer view

add a debug setting "InvisibleObjectsInMemoryTime" to adjust the time invisible objects stay in memory.

added getAs and setAs to LLUnit to make it clearer how you specify units
removed accidental 0-based indexing of periodicRecording history...
should now be consistently 1-based, with 0 accessing current active recording
removed per frame timer updates of all historical timer bars in fast timer display
added missing assignment operator to recordings

SH-4264: interesting: Content near edges of screen does not load

Disable asserts in CalculateTangentArray (discussed with davep) to avoid debugging interruptions from bad assets

SH-4261: interesting: crash in LLViewerRegion::addToVOCacheTree

changed Units macros and argument order to make it more clear
optimized units for integer types
fixed merging of periodicrecordings...should eliminate duplicate entries in sceneloadmonitor history

MAINT-2632 speculative guards in display_startup based on prevalence of crashes ending there (no repro, unfortunately)