Fixed #include of <hash_set> which is deprecated in VS2015 and will be removed.
Fixed #include of <hash_set> which is deprecated in VS2015 and will be removed.

Detailed error:
...\VC\INCLUDE\hash_set(17): error C2338: <hash_set> is deprecated and will be REMOVED. Please use <unordered_set>. You can define _SILENCE_STDEXT_HASH_DEPRECATION_WARNINGS to acknowledge that you have received this warning. (compiling source file ..\..\..\src\test\hashtable.cpp).

seahorn/z3,seahorn/z3,conceptofproof/z3,mschlaipfer/z3,seahorn/z3,kyledewey/z3,wujunzero/z3,mschlaipfer/z3,seahorn/z3,conceptofproof/z3,wujunzero/z3,wujunzero/z3,kyledewey/z3,kyledewey/z3,conceptofproof/z3,kyledewey/z3,mschlaipfer/z3,conceptofproof/z3,conceptofproof/z3,conceptofproof/z3,kyledewey/z3,wujunzero/z3,wujunzero/z3,seahorn/z3,kyledewey/z3,mschlaipfer/z3,mschlaipfer/z3,seahorn/z3,mschlaipfer/z3,wujunzero/z3