HPCC-8572 Std.Date functionality

Time support added to Std.Date; new timelib plugin; stringlib
modifications to support time; updated tests for new Std.Date
functionality; additional date manipulation functions for
Gregorian dates.

Signed-off-by: Dan S. Camper <dan.camper@lexisnexis.com>

plugins/timelib/timelib.cpp

@@ -600,7 +600,7 @@ TIMELIB_API void TIMELIB_CALL tlSecondsToString(size32_t &__lenResult, char* &__
     const size_t    kBufferSize = 256;
     char            buffer[kBufferSize];
 
-    memset(buffer, kBufferSize, 0);
+    memset(buffer, 0, kBufferSize);
 
     tlGMTime_r(&theTime, &timeInfo);