PopByAge overlay, initial commit (outline that follows original bars, still only one slider)
Minor adjustment to avoid "hairlines" between bars
PopByAge overlay, color time slider by region + making way for second slider
PopByAge overlay, refactoring to allow arbitrary time slider ID's and attribute names
PopByAge overlay, adding second time slider, writes to URL state (but not yet wired with overlay)
PopByAge overlay, working version
PopByAge overlay, adding overlay mode to state (accessible via URL)
Issue #21: Display pop numbers for overlay, initial commit switching off year labels and ticks in time slider
Issue #21: Display pop numbers for overlay, both sliders display total pop numbers
Issue #21: Display pop numbers for overlay, "simple" popbyage mode shows year labels + markers
Merge commit '1a83fb80d345b1d60c56622cf9353f6f86a7e62a' into popbyage-overlay
Popbyage color for world/region bug popped up again due to merge issue
Issue #23: Toggle timesliders, adding resizable button, non-functional
Issue #23: Toggle timesliders, functional settings button, checkbox, history/URL
Browser history broken, real fix + decoupling tools from chapters regarding tool model states
Issue #36: Updating year ranges on both time sliders, setting same initial year
Issue #36: Setting overlay to disabled as default
Merge branch 'develop' into popbyage-overlay

Conflicts:
	src/tools/incMountain/incMountainChapterController.js
	src/tools/popByAge/popByAgeChapterController.js
	src/tools/popByAge/popByAgeToolView.js
Fixing merge error + moving captions to new i18n file
Fixed captions for pop by age menu (dgettext was missing domain key)