cat: add -A, -E and -T flags

[bapt]

Summary

Support cat -A, -E and -T, which are commonly used by Linux shell
scripts. -E prints a "$" at the end of each line, -T renders tabs
as ^I, and -A is equivalent to -vET.

Discussed with: jrtc27

[ziaee]

bin/cat/cat.1

87

Please move this after line 80 for alphasort

bin/cat/cat.c

169

Can this be moved to after 165 for alphasort?

175

Can this be moved to after line 171 for alphasort?

190

Can this be moved to after line 186 for alphasort?

The reason is because whenever I have manuals where the options are jumbled up, the code also has jumbled up options.

bin/cat/tests/cat_extra_test.sh

7

Silly nit: I think you have an extra "#" here.

[jrtc27]

Minor nits on the implementation but looks functionally correct. Will defer to Alex and others for finessing the manpage.

bin/cat/cat.c

106

Should this be in the same order as the switch?

173–176

188–191

[ziaee]

bin/cat/cat.c

106

Oh yeah I like that