tigefa4u projects Trac

Strike-through the ticket id in a TracSearch listing. Provides feature #2859.

TracSearch had an extra page link when the number of hits was a multiple of `RESULTS_PER_PAGE`

Propagate the `TracError` message to the `HTTPInternalError`. This is needed in case the message is a `Markup` object.

highlight search terms in source browser (fixes #2648)

add checkbox to new ticket form for adding an attachment after submitting the ticket (fixes #588)

sqlalchemy:
* revert changes to `setup.py`
* actually delete file `patch` just made empty

sqlalchemy: initial working implementation

create sandbox branch for SQLAlchemy support

VcRefactoring: support for scoped repositories which are not full self-contained (#1830)
* don't store base paths which are coming from outside of the repository scope
* introduced specialized versioncontrol related exception:
* `NoSuchChangeset`
* `NoSuchNode`
* refactored the `TracError` usage to either use one of the above or the use the `TracError(...)` style instead of the `TracError, ...` style
* fix a potential bug when getting the change summary from the Changeset.get_changes

Thanks to Manuzhai for the initial work on this topic.

Follow-up to r2990: don't automatically enable the version control plugin during initenv. Instead simply warn the user about the repository being unavailable, if this is the case