Corrected a typo in Tessellator#addQuadraticVertex()

Fixes #2648 - corrected a typo in a5cbb0e2
Fixed error reporting for bez/quad/curve vertices

When user calls bezierVertex()/quadraticVertex()/curveVertex() and does
not call beginShape()/beginShape(POLYGON) before or forgets to specify
first vertex(), proper error message is shown.
fix firstline when modifying lines above it (fixes #2654)
Merge remote-tracking branch 'original/master'
error bar, old offset removed
ECS, 3 secs feels like a decent compromise
Add Spanish language
Fix typo "platforms" in PDE.properties
Merge pull request #2691 from federicobond/es-language

Add Spanish language
Add Dutch language
Merge pull request #2693 from AmnonOwed/FixTypoProperties

Fix typo "platforms" in PDE.properties
Merge pull request #2694 from AmnonOwed/AddDutchLanguage

Add Dutch language
fix indents and cleanups
merging changes for languages
slightly more automatic means of adding languages
add French support (pull #2965)
add French support (pull #2965)
Localize status messages and contributions panel
Disable file drag & drop for read-only sketches
Merge pull request #2696 from federicobond/improve-localization

Localize status messages and contributions panel