Fix Windows Installed Date

Fixes #225. The installed date was only ever gathered at compile time
and not each and every time the ossec-installer was run on each system.
This would result in the installed date being the same on all systems
and equal to the time when the installer was compiled.

This makes me wonder if installed date was actually supposed to be
something like 'compiled date'. I'm going to go with it being a bug
though just because of the naming of everything.

This bug has likely existed for quite some time but was only recently
discovered becuase I moved the installed date into the win32ui making it
more visible to end users.

The current time should now be gathered on every run of the installer
and updating VERSION.txt with the information. Also, the issue of the
seconds being cut off should hopefully no longer be an issue as well
since the new method of getting the time shortens the string due to the
difference in the way the time is formatted.
Fix Windows Installed Date

Must do create a user defined variable which can only be done using the
'/global' option currently instead of doing a constant so that a
StrCpy() can be done against the data returned from GetTime().

Previously, the data in the shared variables ($0, $1, etc) had the
potential to change which would also change what was getting stored in
CURRENTTIME. Doing the StrCpy() fixes this issue.
Make 'var' in ossec-installer.nsi lowercase
Merge pull request #227 from awiddersheim/fix_win_install_time

Fix Windows Installed Date