libcolord: Register a log handler when using lcms2
trivial: Split up cd_util_write_tag_ascii() to include a string version
libcolord: Add functionality to set and get the profile characterization data
trivial: Set the context_id when creating the lcms2 profiles

In the future we can use this to extract a better error message.
trivial: Fix a tiny memory leak in the private self test program
libcolord: Set an instance GError when lcms does the error callback
libcolord: Return details errors when reading or writing a tag fails
trivial: Do not crash when trying to dump an invalid ICC profile
trivial: Do not promote the test ICC profile from V2 to V4

We actually want to test the cmsSigProfileDescriptionMLTag functionality.
trivial: Split up the CdIcc serialization functionality into a new method

No functional changes...
libcolord: Work around a bug in cmsSaveProfileToMem()

We'll go back to the proper method when the upstream bug has been found and fixed.