Fixed wrong usage of strftime.

Fixed nasty symbols in alethzero messages.

The buf length of 9 was too short, there are locales like "HH:MM::SS PM",
and who knows what else.

Increased buffer to 24, and check for the failure condition.
Merge pull request #45 from SharpCoiner/master

Fixed wrong usage of strftime.
Merge pull request #36 from subtly/master

macos app bundle
Fix type in cmake.
more cmake fixes.
Remove some debug output.
Make hash construction safer.