More PleineLune bugfixes & theming #100

Hi Piwik team !

This PR contains some bug fixes:

• SegmentEditor > missing the "Add new segment" button in Zeitgeist (when there are 10 custom segments)
• Enlarge the clickable area of the Site selector
• SegmentEditor > when editing a segment, the text overlaps with icon. Also there is some remaining pixels on the top left.
• API + Widgets pages > Site selector missing

And some PleineLune theming:

• Map > Theme
• jQplot > Metrics picker above graph not themed
• Period Selector > Calendar is not themed
• Login form not fully themed
• Visitors > Visitor Log > Tooltip not themed (eg. Hover on one Action)
• DataTable > on Hover on a datatable Column name, the Tooltip with documentation is not themed
• DataTable > Referrers > Overview. In the table of reports on the left, The list of reports appear on white backgrounds.
• All Websites > First column looks OK but other columns have white border around cells
• Admin > yellow tooltips are not themed (eg. in Geolocation)
• Admin > H3 style is not themed(eg in Admin>DB Usage)
• Annotations > Edit one. Save + Cancel buttons not themed. (buttons also used in Admin, Email reports, etc)
• Visitor > Custom Variables > Click on a custom variable. The subtable loads. This table has alternate styles. The dark grey font color has not enough contrast.

Cheers,
Thomas.

Small update:

• Style text, link & sparklines on popin, like Row Evolution