patch for preview() function in Windows

This changes the preview() function to run better code for Windows.

Julia v0.6 pre-release

This release deprecates two functions, one of which clashes with Base. They'll be removed in the next release.

• fill() to be replaced with fillpath()
• stroke() to be replaced with strokepath()

Fixes for 0.5.1 and 0.6.x

• compatibility with Julia 0.5.1 (yes, I know...)
• rule() added
• fixes and doc updates

compositing and misc additions, some changes for v0.6

• compositing
• grids
• edits for v0.6

Tests pass on Windows

• tests changed so that they pass on Windows/Appveyor
• some minor additions, e.g. hypotrochoids, another ellipse method

Make docs on Travis the way they should have been made

With this release the docs have been moved into the gh-pages branch.

v0.7.0 Documentation updates

Minor documentation updates and some utility functions.