Merge pull request #43 from smuzaffar/master

Allow checkdeps to create poison files for deleted packages
warn about all missing git configuration settings at once, and check for the user repository on GitHub before using it
Merge pull request #44 from fwyzard/improve-user-checks

improve checks for user configuration and repository
Support for git-cms-showtags.
Merge pull request #46 from ktf/master

Support for git-cms-showtags.
make the final check on the user repository optional
run git-cms-init only if the repository is not initialised
check for a custom set "my-cmssw" remote
Merge pull request #48 from fwyzard/check_custom_remote

Check custom remote
check for a custom set "my-cmssw" remote
do not re-fetch from official-cmssw before adding a package
Merge pull request #49 from fwyzard/check_custom_remote_fix

check for a custom set "my-cmssw" remote
Merge pull request #50 from fwyzard/do_not_fetch_in_git-cms-addpkg

Do not fetch in git cms addpkg
run git-cms-init only if the repository is not initialised
Merge pull request #51 from fwyzard/reduce_passphrase_request_part2

run git-cms-init only if the repository is not initialised
check for $CMSSW_BASE before using it
Merge pull request #52 from fwyzard/check_CMSSWBASE_before_using_it

check for $CMSSW_BASE before using it
Use password cache if available.
Merge pull request #53 from ktf/credential-cache-support

Use password cache if available.