Merge branch '32-versions-of-image-libraries-are-evaluated-by-hand-and-given-as-parameters-on-the-compiler-command-line' into 'master'

Resolve "versions of image libraries are evaluated by hand and given as parameters on the compiler command line"

Closes #32

See merge request !41

Matplotlib is not a build time dependency

See merge request !40

Relax matplotlib requirement

Closes #31

See merge request !39

It's only used in one utility function therefore the import
has been moved within the function and the requirement moved to
run_constrained.

Fixes #31

Add tests to detect the problem reported on this issue

Closes #30

See merge request !36

Revert "Merge branch 'issue-29' into 'master'"

See merge request !35

This reverts merge request !33

Quick fix for the issue #29. I still don't know why this artefact is not visible.

See merge request !33

Resolve "Cannot read CMYK jpeg images"

Closes #19

See merge request !31

Merge branch '19-cannot-read-cmyk-jpeg-images' of https://gitlab.idiap.ch/bob/bob.io.image into 19-cannot-read-cmyk-jpeg-images

Merge branch '19-cannot-read-cmyk-jpeg-images' of https://gitlab.idiap.ch/bob/bob.io.image into 19-cannot-read-cmyk-jpeg-images

Add a utility function to convert images from matplotlib format to bob format

See merge request !32

fixed docs badge urls, see bob/admin#2

See merge request !30

Mention about bob.io.base.peek in user guide.

Closes #24

See merge request !29

Fixes #24

Merge branch '27-non-templated-functions-implemented-in-header-files-need-to-be-inlined' into 'master'

inlined non-templated functions implemented in header

Closes #27

See merge request !28

Moved test function into its own extension

Closes #23

See merge request !27