(In [5316]) fixes #2637 render graphs using imageGraph plugin. If API is Piwik 1.5 or older, still render graphs using the old way.

(In [5582]) * fixes matomo-org/matomo#2706, #2828, #2704, refs matomo-org/matomo#1721, #2637, #2711, #2318, #71 : horizontal static graph implemented

• fixes Static Graph: better graphs when date range period parameter matomo#2788, refs Metadata improvements to generate static graph image URL matomo#2670, #1721, Use ImageGraph plugin to render graphs #2637, Use only ImageGraph Plugin to render Graphs #2711 : default graph type logic moved to ImageGraph API, improved date/period logic, new parameter graphs_default_period_to_plot_when_period_range
• fixes Graphs should support Unicode characters & other improvements matomo#2704, #2804, refs ImageGraph: export reports as graph matomo#1721 : pChart updated to 2.1.3, pChart code removed from Piwik code, OOP refactoring, support for unifont.ttf if present in ImageGraph/fonts, testAllSizes now uses report metadata ImageGraphUrl
• refs Plugin to provide PDF export of data matomo#5491 : space between report title and report table reduced to avoid page overflow
• refs ImageGraph: graphs should display % values matomo#2829 : TODO display percentages
• r5544, r5547, r5549 merged