Refactor Unix signals.

Summary:
- Consolidate Unix signals selection in UnixSignals.
- Make Unix signals available from platform.
- Add jSignalsInfo packet to retrieve Unix signals from remote platform.
- Get a copy of the platform signal for each remote process.
- Update SB API for signals.
- Update signal utility in test suite.

Reviewers: ovyalov, clayborg

Subscribers: chaoren, jingham, labath, emaste, tberghammer, lldb-commits

Differential Revision: http://reviews.llvm.org/D11094

llvm-svn: 242101
diff --git a/lldb/scripts/interface/SBPlatform.i b/lldb/scripts/interface/SBPlatform.i
index a6c4dfb..9234a3d 100644
--- a/lldb/scripts/interface/SBPlatform.i
+++ b/lldb/scripts/interface/SBPlatform.i
@@ -188,6 +188,9 @@
     lldb::SBError
     SetFilePermissions (const char *path, uint32_t file_permissions);
 
+    lldb::SBUnixSignals
+    GetUnixSignals();
+
 };
 
 } // namespace lldb