820392 - repository hostname validation

Allow not fully qualified names as a repository URL. Also allow
numbers as first characters. Added some specs for edge cases.
Move all validators to one place

Since validators are not models they should not be in app/models.
All validators are now placed in lib/validators/ and each has its own
definition file.

All validators are in module Validators. When you want to use custom
validation in model you must specify a validator class so it gets loaded
by autoloader. If you use DSL provided by ActiveModel::Validations for
custom validator you'll receive unknown validator error because models
are loaded before lib. That's why we should always use validates_with
when dealing with custom validators.
Code cleanup

To obtain boolean as a result !! is usually used. Also parenthesis in
method definiton for arguments should be used.
Repository feed validation moved to validator

Validation was performed in controllers in API and UI which was not DRY.
This logic is extracted in existing KatelloUrlFormatValidator that was
not used anywhere. This validator uses KatelloUrlHelper which I left
intouched because it can be reused more easily than validator itself.

Since tests did not specify feed because it was not required until now I
had to add feed info wherever fake repository was created.
cli completion - fix in sed expression
Merge pull request #1390 from tstrachota/completion_fix

cli completion - fix in sed expression
Merge pull request #1375 from ares/bug/820392-repository_hostname_validation

Bug/820392 repository hostname validation
Revert "Pylint - Updates to remove disablement of pylint warnings present in"

This reverts commit f5d62e42ae52faca1b0a5aa38f272765cc538e66.
resolve pylint errors on Fedora 19

addressing:
+ pylint --rcfile=/etc/spacewalk-pylint.rc --additional-builtins=_ katello
************* Module katello.client.core.utils
W1401:296,0: Anomalous backslash in string: '\0'. String constant might be missing an r prefix.
W1401:298,0: Anomalous backslash in string: '\0'. String constant might be missing an r prefix.
W1401:309,0: Anomalous backslash in string: '\0'. String constant might be missing an r prefix.
W1401:320,0: Anomalous backslash in string: '\|'. String constant might be missing an r prefix.
Merge pull request #1391 from xsuchy/pull-req-pylint-F19

resolve pylint errors on Fedora 19
894480 - remove PyXML dependency

Quote from BZ:
I've opened up a Fedora 19 Feature to remove PyXML due to a combination of it being dead upstream for many years and that when it's installed, the python stdlib overwrites its own xml module with PyXML.  This combination leads to errors because PyXML's code is older and contains bugs that have been fixed in the stdlib.
make travis happy
Merge pull request #1389 from xsuchy/pull-req-bz894480

894480 - remove PyXML dependency
Translations - Download translations from Transifex for katello-cli.
Translations - Download translations from Transifex for katello.
Translations - New translations from Transifex for katello.
Translations - Update .po and POTFILES.in files for katello-cli.
Translations - Update .po and .pot files for katello.
Merge pull request #1399 from jlsherrill/update_translations

end of sprint update of translations