Documentation: minor fixes

* application.md: fix formatting, fix table name from subjects to base_subject
* database.md: add missing semicolon to DB creation instructions
* shibbolethidp.md: fix reference to simpleaggregation.md
* shibbolethsp.md: add list of attributes to request from federation
Configuration: add missing ProxyPass exclusion

The sample Apache groups.conf would pass ALL requests on port 443 to
Tomcat, including requests to /Shibboleth.sso that should be handled
internally by mod_shib.

Add requests to /Shibboleth.sso and /shibboleth-sp (where the stylesheet
for ShibSP error pages lives) as an exception.
Documentation: fix again the formatting in application.md
Doc: Aggregation: remove EntityReference

Remove the EntityReference element from the sample SP aggregation
snippet.

The line was not needed there at all - this element should be used with
names of attributes that contain the entityID(s) of IdPs to query - this
is not a likely use case with the eduPersonEntitlement attribute used in
this example.
Aggregation: sharedToken aggreg in doc and config.

Include documentation and sample config for aggregation by
auEduPersonSharedToken.

Note that this configuration uses the NameID format
''''urn:oasis:names:tc:SAML:2.0:nameid-format:persistent'''' to
represent the auEduPersonSharedToken value - and relies on the Groups
IdP mapping this back to a Principal name with the following
configuration line (also included in this commit):

    <resolver:PrincipalConnector xsi:type="pc:Direct" id="sharedToken" nameIDFormat="urn:oasis:names:tc:SAML:2.0:nameid-format:persistent"/>
Documentation: fix markup in simpleaggregation.md
Merge pull request #8 from University-of-Auckland/develop-aggregation-sharedToken

Aggregation: sharedToken aggreg in doc and config.
Merge pull request #6 from University-of-Auckland/aaf-develop

Minor fixes to documentation - and Apache config file.