Adding LDAP StartTLS support

Some LDAP server do not allow authenticate with unencrypted password.
This patch is adding the StartTLS support which takes care of the
encryption.

In order to enable the StartTLS, go to "System Settings" and select the
"Enable StartTLS" in the Authentication section. Then make sure that you
add your LDAP certificate into the Java keystore:

$ keytool -import \
          -file /etc/pki/tls/certs/cacert.pem \
          -alias myName \
          -keystore /var/lib/gitbucket/keystore

You can list all keys from the keystore like this:

$ keytool -list -keystore /var/lib/gitbucket/keystore
Upgrade to scalatra-forms 0.0.4
(refs #185)Add -Dsbt.log.noformat=true option
Fix test case.
(refs #114)Add remove option to user management.
(refs #114)Remove user related data when user is removed.
(refs #114)Add TODO to helpers#activityMessage()
(refs #114)Add group deletion.
(refs #114)Bug fix
(refs #114)Disable link for disabled users.
(refs #114)Remove unnecessary database accessing.
(refs #114)Add functionality to remove account by themselves.
Fix test case.
(refs #177)Fix regular expressions for issue link conversion.
(refs #189)Fix Wiki page editing via redirecting from unexisting page.
(refs #181) Fixed bug in charset.
Moving keystore definition into settings
add HARDWRAPS option
Use the system keystore by default

Default system keystore is in:
$JAVA_HOME/lib/security/jssecacerts
or in:
$JAVA_HOME/lib/security/cacerts

Custom keystore can be set either in /etc/sysconfig/gitbucket by
specifying the following option:
GITBUCKET_JVM_OPTS="-Djavax.net.ssl.trustStore=/path/to/your/cacerts"
or in Gitbucket's System Settings.
Upgrade to scalatra-forms 0.0.6.