added support for scalechannels
fixed behaviour of ComposeChannels
fixed num_channels
fixed docstrings
Fixed Pyflakes warnings regarding unused imports
Merge pull request #32 from spiglerg/master

Fixed ComposeChannels and bugs with num_channels()
Introduces OffsetTimeFn
Fixes Sweeper by adding step_offset and OffsetTimeFn
Allow any arbitrary direction for moving patterns
Merge pull request #33 from Tobias-Fischer/sweeper_improvement

Allow any arbitrary direction for moving patterns
Fixed bug in FileImage caching, when matrix dimensions are changed

When a cached FileImage was first viewed using the default matrix
dimensions and then installed on a GeneratorSheet with different
dimensions, it would continue to present the cached image with
wrong dimensions.
All patterns have the same orientation when direction is used
Merge branch 'master' of https://github.com/ioam/imagen
Added icon to README for imagen doc build status
Merge branch 'master' of https://github.com/ioam/imagen
Allow scaling value