List of backwards compatibility fixes

As NGLess uses a version declaration string at the top of script means that NGLess can change its behaviour depending on the version used in the script.

NGLess 1.1

• The way that CIGAR sequence lengths are computed has changed to match samtools. This implies that the computation of min_match_size and min_identity_pc have slightly changed.
• Starting in NGLess 1.1, countfile reorders its input if necessary.
• count now handles multiple lines of comments at the top of its functional_map arguments

NGLess 0.8

• select changes how a corner case is handled.

NGLess 0.6

• The count function now defaults to include_minus1 being true.

NGLess 0.5

• The preprocess function now modifies its argument. Older code using

preprocess(input) using |r|:
    ...

is automatically treated as:

input = preprocess(input) using |r|:
    ...