Fix direct compilation failed：
fix compile thirdparty in ubuntu will install libs to lib dir instead of lib64
fix compile error in gcc5 due to the defect of c++11 (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=60970)
fix gcc version check will not work on some OS
A bad tablet is always be chosen to do compaction, and failed again
and again, which may block compaction of other tablets.
Add a BE config 'min_compaction_failure_interval_ms' to avoid choosing
bad tablet again at a certain interval, so that other tablets have
chance to do the compaction.
Also fix a bug that using avg() function on varchar column return
unexpected exception.
* Reduce UT binary size
Almost every module depend on ExecEnv, and ExecEnv contains all
singleton, which make UT binary contains all object files.
This patch seperate ExecEnv's initial and destory to anthor file to
avoid other file's dependence. And status.cc include debug_util.h which
depend tuple.h tuple_row.h, and I move get_stack_trace() to
stack_util.cpp to reduce status.cc's dependence.
I add USE_RTTI=1 to build rocksdb to avoid linking librocksdb.a
Issue: #292
* Update
2. add 2 new proc '/current_queries' and '/current_backend_instances' to monitor the current running queries.
3. add a manual compaction api on Backend to trigger cumulative or base compaction manually.
4. add Frontend config 'max_bytes_per_broker_scanner' to limit to bytes per one broker scanner. This is to limit the memory cost of a single broker load job
5. add Frontend config 'max_unfinished_load_job' to limit load job number: if number of running load jobs exceed the limit, no more load job is allowed to be submmitted.
6. a log of bug fixed
