Reword some comments and fix some typos.

git-svn-id: http://svn.savannah.nongnu.org/svn/avr-libc/trunk@2322 1084037a-409f-4a99-8160-1a4b3577d4c1
Edited daylight_seconds() for readability

git-svn-id: http://svn.savannah.nongnu.org/svn/avr-libc/trunk@2323 1084037a-409f-4a99-8160-1a4b3577d4c1
Edited gm_sidereal for readability

git-svn-id: http://svn.savannah.nongnu.org/svn/avr-libc/trunk@2324 1084037a-409f-4a99-8160-1a4b3577d4c1
Edited comments of isLeap() for readability

git-svn-id: http://svn.savannah.nongnu.org/svn/avr-libc/trunk@2325 1084037a-409f-4a99-8160-1a4b3577d4c1
Edited lm_sidereal() for readability

git-svn-id: http://svn.savannah.nongnu.org/svn/avr-libc/trunk@2326 1084037a-409f-4a99-8160-1a4b3577d4c1
Edited comments of mk_gmtime() for readability

git-svn-id: http://svn.savannah.nongnu.org/svn/avr-libc/trunk@2327 1084037a-409f-4a99-8160-1a4b3577d4c1
Simplified month_length() somewhat

git-svn-id: http://svn.savannah.nongnu.org/svn/avr-libc/trunk@2328 1084037a-409f-4a99-8160-1a4b3577d4c1
Edited comments of moon_phase()

git-svn-id: http://svn.savannah.nongnu.org/svn/avr-libc/trunk@2329 1084037a-409f-4a99-8160-1a4b3577d4c1
Edited solar_declination() for clarity

git-svn-id: http://svn.savannah.nongnu.org/svn/avr-libc/trunk@2330 1084037a-409f-4a99-8160-1a4b3577d4c1
Edited sun_rise() and sun_set() for clarity

git-svn-id: http://svn.savannah.nongnu.org/svn/avr-libc/trunk@2331 1084037a-409f-4a99-8160-1a4b3577d4c1