v4: implement meta/tags endpoint
Fix XML declaration in the default icon.
Make bundle/diagram endpoint use the dynamic icon endpoint.
Add documentation refernces to icon and readme API endpoints.
Merge pull request #189 from frankban/svg-fixes

Svg rendering fixes

Make the bundle/diagram endpoint refer to the dynamic charm/icon one, so that icon rendering is faster and also the default icon is displayed when the charm has no icon.
Also fix the default icon rendering, avoiding new lines at the beginning of the SVG (XML declaration).
Merge pull request #188 from rogpeppe/081-meta-tags

v4: implement meta/tags endpoint

As discussed online, we choose tags over categories if specified.
Improve output of charmd.
Improve charmd command line usage in readme.
Merge pull request #190 from frankban/charmd-logs

Improve output of charmd.
Added pagination to search queries

A new skip parameter can be added to search queries and the results
will start from that offset in the overall search results.
Merge pull request #192 from mhilton/search-pagination

Added pagination to search queries

A new start parameter can be added to search queries and the results
will start from that offset in the overall search results.