Convert all python objects in our API to use overload the __str__ method
instead of the __repr__. __repr__ is a function that should return an
expression that can be used to recreate an python object and we were using
it to just return a human readable string.

Fixed a crasher when using the new implementation of SBValue::Cast(SBType).

Thread hardened lldb::SBValue and lldb::SBWatchpoint and did other general
improvements to the API.

Fixed a crasher in lldb::SBValue::GetChildMemberWithName() where we didn't
correctly handle not having a target.

llvm-svn: 149743
diff --git a/lldb/test/python_api/symbol-context/TestSymbolContext.py b/lldb/test/python_api/symbol-context/TestSymbolContext.py
index b601920..ad0a55b 100644
--- a/lldb/test/python_api/symbol-context/TestSymbolContext.py
+++ b/lldb/test/python_api/symbol-context/TestSymbolContext.py
@@ -68,7 +68,7 @@
             substrs = [os.path.join(self.mydir, 'a.out')])
 
         compileUnit = context.GetCompileUnit()
-        self.expect(repr(compileUnit), "The compile unit should match", exe=False,
+        self.expect(str(compileUnit), "The compile unit should match", exe=False,
             substrs = [os.path.join(self.mydir, 'main.c')])
 
         function = context.GetFunction()