Relax the check for the value 91. Related to #917
Check for ArrayResult AND Array before building an array of result
Query SI every 5 seconds in case of an error
Made perfmon_result_t::internal_map_t not use a scoped_ptr_t.
Merge branch 'next' into sam_949
Made perfmon_result_t::get_map be private.  Also fixed a debug mode compilation error in perfmon/archive.cc.
Merge branch 'next' into sam_949

Conflicts:
	src/perfmon/core.cc
added auto_reconnect to Ruby driver
with_fields smoke tested
tests
docs
added tests
Adds server support for difference.
Adds array arith to js and python drivers.
Adds tests for difference.
Adds docs for array difference.
Merge branch 'next' into sam_949
fixed ast.py st
Makes difference work on streams.
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