converted a bunch of narrowing implicit conversions to explicit

indra/llaudio/llaudiodecodemgr.cpp

indra/llcommon/linden_common.h

indra/llcommon/llevents.cpp

indra/llcommon/llmd5.cpp

indra/llcommon/llpreprocessor.h

indra/llcommon/llsdserialize.cpp

indra/llcommon/llsdserialize_xml.cpp

indra/llcommon/llsdutil.h

indra/llcommon/llstat.cpp

indra/llcommon/lltimer.cpp

indra/llcrashlogger/llcrashlogger.cpp

indra/llimage/llimagej2c.cpp

indra/llinventory/llinventory.cpp

indra/llmath/llcalcparser.h

indra/llmath/llvolume.cpp

indra/llmath/m4math.cpp

indra/llmessage/llbufferstream.cpp

indra/llmessage/llcurl.cpp

indra/llmessage/llhttpclient.cpp

indra/llmessage/llmime.cpp