Org: optimize

[masatake]

The Org parser is incredibly slow.

The original:

[yamato@dev64]~/var/ctags-github% ./ctags --totals /home/yamato/var/emacs/doc/misc/org.org
1 file, 22606 lines (802 kB) scanned in 98.8 seconds (8 kB/s)
625 tags added to tag file
625 tags sorted in 0.00 seconds
longest tag line = 127

With this pull request:

[yamato@dev64]~/var/ctags-github% ./ctags --totals /home/yamato/var/emacs/doc/misc/org.org
1 file, 22606 lines (802 kB) scanned in 0.6 seconds (1291 kB/s)
624 tags added to tag file
624 tags sorted in 0.00 seconds
longest tag line = 127

It becomes 150% faster with this pull request.

BTW, this parser doesn't fill scope fields.

[masatake]

However,... one tag is lost with this change.

---

I inspected this. The missing one should not be tagged.

[codecov]

Codecov Report

Base: 82.84% // Head: 82.84% // Increases project coverage by +0.00% 🎉

Coverage data is based on head (d068172) compared to base (12ff207).
Patch coverage: 0.00% of modified lines in pull request are covered.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #3611   +/-   ##
=======================================
  Coverage   82.84%   82.84%           
=======================================
  Files         223      223           
  Lines       54280    54279    -1     
=======================================
  Hits        44966    44966           
+ Misses       9314     9313    -1     

Impacted Files	Coverage Δ
optlib/org.c	0.00% <0.00%> (ø)

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[masatake]

I found the Org parser extracts many noises. It may be rewritten more line-oriented way.