Shift the origin and/or apply scaling in charts

This accounts for both under and overflow. Added a test requiring the
origin shift in order to correctly render points. The odd artifact is
the labels on the X axis (all 1) due to the number of significant
figures displayed.

Change-Id: I6247a00ce84c7d2012cde692e24b717a174c2752
Ensure the tool tip item gets the correct number

The tool tip item must display the numbers that correspond to the
full double precision representation shown on the axes.

Change-Id: I0bc1296b6d1d466fa6624868496f2a09c756882b
Update baselines for the fontconfig tests.

Change-Id: Id01ffea2cce24a7714eee009fe1c9e20744d6065
Merge topic 'new-fontconfig-baselines' into master

7224adb4 Update baselines for the fontconfig tests.
Merge topic 'charts-double-precision' into master

6cd8f93d Ensure the tool tip item gets the correct number
7cee41db Shift the origin and/or apply scaling in charts
Additional base line for double prevision test

Windows displays 3 figures after e rather than just what is needed.

Change-Id: I3cf2209fb19c8f5f50001451dedf4e3d05009930
Merge topic 'charts-double-precision' into master

1b6bed08 Additional base line for double prevision test