Merge pull request #144 from toxeus/fixDescribe

build_tar.sh: fix version retrieval with git describe
opentxs: fix -Wtautological-undefined-compare

Found by clang++ 3.5:
"Reference cannot be bound to dereferenced null pointer in
well-defined C++ code; comparison may be assumed to always
evaluate to true/false"
OTTransaction: fix -Wabsolute-value

Found by clang++ 3.5
Merge pull request #145 from toxeus/fixTautological

clang++ 3.5: fix compile errors
Version: Add Version.hpp Header file
Cleanup .gitignore
opentxs-cli: Add version command
Version/CMake/Packaging: Remove Package release on filename
Merge pull request #146 from lclc/opentxsVersionCommand

opentxs version command
build_tar.sh: fix version fetching from git tag
Merge pull request #149 from toxeus/fixTagVersion

build_tar.sh: fix version fetching from git tag
fix bug in OTSymmetricKey.cpp
Merge pull request #151 from da2ce7/changepw_fix

fix bug in OTSymmetricKey.cpp when useing changepw command
build_tar.sh: re-fix version fetching from git tag