No need for calling SecureZeroMemory for already initialized buffers

Signed-off-by: Sven Strickroth <email@cs-ware.de>
Reduce usage of extra buffers and no need to SecureZeroMemory if we know the length of strings

Signed-off-by: Sven Strickroth <email@cs-ware.de>
Add cli command for displaying TortoiseGit signing key fingerprint

Signed-off-by: Sven Strickroth <email@cs-ware.de>
Rename DLL names to avoid DLL hell, "_tgit" prefix added

SciLexer.dll -> SciLexer_tgit.dll
libgit2.dll -> libgit2_tgit.dll
zlib1.dll -> zlib1_tgit.dll

Signed-off-by: Sup Yut Sum <ch3cooli@gmail.com>