man: commit some obsolete code

before i added preprocessor support, i added this code that tries
to distinguish between "unknown" macros that end up as a comment
and such that are just printed as regular text.
this turned out not to be right approach, but it gives hints
as to how such a thing could be implemented.
thus i'm committing this for documentation reasons, just to revert
it in the next one.
Revert "man: commit some obsolete code"

This reverts commit 383baa0a4f6efd5f9baf7baddd06940ad8afab32.
Revert "man: fall back to case-insensitve when a command was not detected"

with the help of a preprocessor, we can now do better cheaply.

This reverts commit 2c9ad81841b013d3dbc4f29a0cb35a6fa0c84bc8.
man: do not crash when .so included file is missing

.so means that a file should be included.
so the existing page was closed, and it tried to open the
included file, failed, but still called close_page later
with ifd still pointing to the old FILE*.
Revert "man: support .Nm, which seems to be a mandoc feature"

The preprocessor is taking care of it now.

This reverts commit 1a8dad1c55abced7d861579dfa340dd0cc09f41a.

Conflicts:

	man.c
solved.
man: support perl manpages, given they use an own dir

perl manpages must reside in man1perl/ man3perl/ respectively.
add manpp, a manpage preprocessor

it turns commonly used mandoc, groff and other junk into nroff
syntax.
the man program without any help of this can display 75% of
all manpages in sabotage correctly, with additional help of
manpp most manpages come out nearly as intended.

current status
=== status report  ===
total manpages  : 8001
buggy manpages  : 1564
total failures  : 7443
unique failures : 128

top bug list:
(the leading number means number of unique manpages using it)
    879 **** Unknown formatter command: .\$
    514 **** Unknown formatter command: .TS
    512 **** Unknown formatter command: .TE
    471 **** Unknown formatter command: .Ds
    471 **** Unknown formatter command: .De
    387 **** Unknown formatter command: .rs
    373 **** Unknown formatter command: .EX
    371 **** Unknown formatter command: .EE
    305 **** Unknown formatter command: .Nm
    281 **** Unknown formatter command: .OP
    269 **** Unknown formatter command: .hw
    222 **** Unknown formatter command: .IN
    221 **** Unknown formatter command: .ti
    211 **** Unknown formatter command: .TQ
    185 **** Unknown formatter command: .\"
    152 **** Unknown formatter command: .FT
    106 **** Unknown formatter command: .Pp
     99 **** Unknown formatter command: .UE
     97 **** Unknown formatter command: .UR
     79 **** Unknown formatter command: .Env
     73 **** Unknown formatter command: .ig
     71 **** Unknown formatter command: .el
     67 **** Unknown formatter command: .Pn
     66 **** Unknown formatter command: .SY
     56 **** Unknown formatter command: .Dv
     55 **** Unknown formatter command: .Top
     44 **** Unknown formatter command: .MT
     41 **** Unknown formatter command: .ME
     39 **** Unknown formatter command: .YS
     39 **** Unknown formatter command: .Fil
     38 **** Unknown formatter command: .fam
     38 **** Unknown formatter command: .URL
     36 **** Unknown formatter command: .hN
     28 **** Unknown formatter command: .CW
     27 **** Unknown formatter command: .Em
     23 **** Unknown formatter command: .it
     23 **** Unknown formatter command: .com
     22 **** Unknown formatter command: .XAA
     22 **** Unknown formatter command: .Ip
     17 **** Unknown formatter command: .XDE
     17 **** Unknown formatter command: .T&
     16 **** Unknown formatter command: .cp
     16 **** Unknown formatter command: .LR
     15 **** Unknown formatter command: .XB
     15 **** Unknown formatter command: .Tp
     14 **** Unknown formatter command: .HD
     14 **** Unknown formatter command: .EQ
     14 **** Unknown formatter command: .EN
     14 **** Unknown formatter command: .D-c
     13 **** Unknown formatter command: .jBu
     13 **** Unknown formatter command: .jBu
     13 **** Unknown formatter command: .Hea
     12 **** Unknown formatter command: .xsu
     12 **** Unknown formatter command: .x-c
     12 **** Unknown formatter command: .CE
     11 **** Unknown formatter command: .NE
     11 **** Unknown formatter command: .L
     10 **** Unknown formatter command: .ind
     10 **** Unknown formatter command: .do
     10 **** Unknown formatter command: .FN
      8 **** Unknown formatter command: .co
      8 **** Unknown formatter command: .Ql
      8 **** Unknown formatter command: .NS
      8 **** Unknown formatter command: .LI
      7 **** Unknown formatter command: .au
      7 **** Unknown formatter command: .TF
      6 **** Unknown formatter command: .cha
      6 **** Unknown formatter command: .bP
      6 **** Unknown formatter command: .CBI
      5 **** Unknown formatter command: .Quo
      5 **** Unknown formatter command: .CRI
      4 **** Unknown formatter command: .vs
      4 **** Unknown formatter command: .Esc
      3 **** Unknown formatter command: .p
      3 **** Unknown formatter command: .Ux
      3 **** Unknown formatter command: .NT
      3 **** Unknown formatter command: .MTO
      3 **** Unknown formatter command: .D-m
      3 **** Unknown formatter command: ./"
      2 0**** Unknown formatter command: .ig
      2 **** Unknown formatter command: .rj
      2 **** Unknown formatter command: .out
      2 **** Unknown formatter command: .off
      2 **** Unknown formatter command: .mso
      2 **** Unknown formatter command: .l
      2 **** Unknown formatter command: .cc
      2 **** Unknown formatter command: .TAG
      2 **** Unknown formatter command: .Sx
      2 **** Unknown formatter command: .Sq
      2 **** Unknown formatter command: .PS
      2 **** Unknown formatter command: .PE
      2 **** Unknown formatter command: .Lb
      2 **** Unknown formatter command: .LK
      1 **** Unknown formatter command: .wid
      1 **** Unknown formatter command: .tim
      1 **** Unknown formatter command: .tab
      1 **** Unknown formatter command: .sho
      1 **** Unknown formatter command: .sep
      1 **** Unknown formatter command: .sch
      1 **** Unknown formatter command: .rn
      1 **** Unknown formatter command: .rea
      1 **** Unknown formatter command: .qui
      1 **** Unknown formatter command: .pro
      1 **** Unknown formatter command: .nul
      1 **** Unknown formatter command: .mod
      1 **** Unknown formatter command: .imp
      1 **** Unknown formatter command: .hel
      1 **** Unknown formatter command: .hea
      1 **** Unknown formatter command: .hc
      1 **** Unknown formatter command: .exp
      1 **** Unknown formatter command: .exi
      1 **** Unknown formatter command: .ech
      1 **** Unknown formatter command: .dum
      1 **** Unknown formatter command: .dat
      1 **** Unknown formatter command: .cop
      1 **** Unknown formatter command: .c2
      1 **** Unknown formatter command: .aut
      1 **** Unknown formatter command: .UC
      1 **** Unknown formatter command: .PU
      1 **** Unknown formatter command: .NH
      1 **** Unknown formatter command: .HR
      1 **** Unknown formatter command: .FTP
      1 **** Unknown formatter command: .Dl
      1 **** Unknown formatter command: .Da-
      1 **** Unknown formatter command: .CT
      1 **** Unknown formatter command: .CIR
      1 **** Unknown formatter command: .CB
      1 **** Unknown formatter command: .Brq
add test for man
add true and false