Add default timezone when system one is missing

Suppresses all the PHP warnings in the error logging.
Merge pull request #38 from oohlaf/timezone

Add default timezone when system one is missing
automatic page refresh support + config setting

Closes: https://github.com/pommi/CGP/pull/35
fix heigth -> height typo
graph: add configurable limit to graph width/height

Closes: https://github.com/pommi/CGP/pull/34
plugin/tail: collectd < 5 backwards compatibility

Closes: https://github.com/pommi/CGP/issues/36
Time left is in seconds (plugin apcupsd)
Merge pull request #40 from oohlaf/apcupsd

Time left is in seconds (plugin apcupsd)
Nginx plugin changed DS types

See https://github.com/collectd/collectd/pull/227
Merge pull request #41 from oohlaf/nginx

Nginx plugin changed DS types
jsrrdgraph: RrdDataFile.js: fix space/tabulation
jsrrdgraph: RrdDataFile.js: splitting fetch into fetch & build
jsrrdgraph: RrdGraph.js: fix some indentation
jsrrdgraph: RrdGraph.js: splitting RrdGraph.prototype.graph_paint into init, fetch and draw
jsrrdgraph: RrdDataFile.js: Add async function (fetch_async) to RrdDataFile
jsrrdgraph: RrdGraph.js: Add RrdGraph.prototype.graph_paint_async method
jsrrdgraph: Change alter for thow
jsrrdgraph: CGP.js: split draw(id) into prepare_draw(id) and draw(id)
Add a configuration option for sync/async choice for the canvas graphs
add graph_type "hybrid" to show canvas on detail page, png on the others