BUG Fixes #144. Users with limited permissions can delete workflows.

- Added canCreate/canEdit/canDelete() to Definition, Action & Transition.
- canEdit+canDelete call WorkflowDefinition#canCreate().
- Made WorkflowField UI buttons disabled based on the canXX() methods.
- Removed disableButton() methods, using canXX() in template directly.
- Added missing docblocks & tests.
#148 Escaped table and field names.

Applied escaping to table (SiteTree_versions) and field
(ID, WasPublished) identifiers to support PostgreSQL
conventions.
Merge pull request #150 from courage-web-solutions/fix-148

Fix #148 Escaped table and field names.
Merge pull request #146 from phptek/issue/144

BUG Fixes #144. Users with limited permissions can delete workflows.
FIX: Fixes regression in 28eaf1d. Incorrect disabling JS logic order.
Merge pull request #152 from phptek/issue/133-b

FIX: Fixes regression in 28eaf1d. Incorrect disabling JS logic order.
NEW Fixes #128. Workflow definition export+import functionality.

Allows for YAML based workflow definitions to be imported into another
SilverStripe installation.

- Workflows are exported from their GridField row, in YAML format.
- Exported workflows can be re-created in another SilverStripe install.
- User & Group relations are maintained if they exist in target CMS.
- Permission checks are made to show/hide import/export UI widgets.
- Refactored getDefaultWorkflowTitle() increments all definition titles.
- Fixed existing tests, added new import/export tests and markdown docs.
- Definition titles added on definition creation, they weren’t previously.
- Removed "Export to CSV" GridField button as it's confusing.
Merge pull request #143 from phptek/issue/128

NEW Fixes #128. Workflow definition export+import functionality.
FIX Fixes #141. Deleting active workflows, results in "stuck" content.
Merge pull request #153 from phptek/issue/141

FIX Fixes #141. Deleting active workflows, results in "stuck" content.
Updated translation sources
Merge pull request #156 from tractorcow/pulls/update-translations

Updated translation sources