Addition of PHP TimeSeries engine as an option, this is the php based flatfile Idea that I blogged about while investigating engine options, phptimeseries maintains the exact same datafile format as mysql for storing the timeseries data and so can be used directly with mysql datafile data without conversion, its much faster than mysql for this very specific application and does not require an additional index.
Although it will save disk space vs mysql it will usually use more disk space than timestore while also not having the averaging options of timestore. However it may provide as a good bridging option especially on windows systems as timestore is not yet tested on windows, while phptimestore only uses standard php file access.

This commit also adds the option to specify the default feed engine to use for creating feeds in settings.php
Merge branch 'master' of https://github.com/emoncms/emoncms
Fixed remnant feed interval selector when using existing feed
Enables negative numbers to display to correct decimal places in table

1) More people are now using emoncms to log import/export of power, which can involve negative data as well as positive. This change enables 'negative value' data to display to correct number of decimal places.
2) Corrects number of decimal places if data is exactly 10 or 100.
Merge pull request #99 from Paul-Reed/patch-2

Enables negative numbers to display to correct decimal places in table
Merge remote-tracking branch 'emoncms/master' into thrx-dev