Enable compatibility with eXist 5.0.0?

[dvglc]

If we want to upgrade to eXist 5.0.0, we need to make some changes in our code (and probably the configuration):

1. [ resolved ] replace all remaining old map assignment operators ":=" by ":" (this is trivial)

2. [ resolved ] get the EXPath httpclient to work, especially with POST requests: POSTing with EXPath http client fails #75

3. [ resolved ] make the app or eXist-db accept URIs of the form "id.salamanca.school/texts/W0015:1.2.3", which currently result in a 50x server error due to an "Invalid URI scheme", obviously being caused by the colon in "W00015:1.2...". This was already a problem with any eXist version above 4.0.0 and was something that I couldn't solve reasonably fast when trying to update to 4.1.0.

4. [resolved] replace some calls to functions in the xmldb module (such as xmldb:set-collection-permissions) by calls to newer functions, see also http://www.exist-db.org/exist/apps/wiki/blogs/eXist/eXistdb500, section "Removed"

[dvglc]

There might be more issues, which can be added here in case we reach this point. However, to me 2.) and 3.) appear quite problematic, and I'm not sure how much time I/we should invest in trying to make eXist 5 work very soon.

[dvglc]

Btw, from what I can tell from working with eXist 5 for roughly a day and a half, there don't seem to be really stunning speed improvements in comparison to our existing 4.0.0 installations...

[dvglc]

The RestXQ servlet still accepts URLs containing a colon, so that 3) could be worked around through making use of RestXQ functions. See also #78