Add the lsmode(MODE) function in the fileio.c extension and use that function

in the .archive implementation.  Add the --append and --dryrun options to
the .archive command and remove the --zip option, making it automatic.

FossilOrigin-Name: 38f28029d16df8489772c27867de8888dd1c26b170861acdc977fd4023939dde

diff --cc manifest
index 3b5c00148939db9da93debcfd3b42179b114f053,7c0f0180e31695cfc254daed97539f4c68af733e..a7fe4fa39dffe9833ebb6f5a903cdedc59eab824
--- 1/manifest
--- 2/manifest
+++ b/manifest
@@@ -1,5 -1,5 +1,5 @@@
- C Return\san\sSQLITE_CONSTRAINT\serror\sif\san\sattempt\sis\smade\sto\sinsert\sduplicate\nentries\sinto\sa\szip\sarchive.
- D 2018-01-10T17:37:58.434
 -C Fix\sminor\sproblems\swith\sthe\snew\s".archive"\scommand\schanges.
 -D 2018-01-10T17:39:54.594
++C Add\sthe\slsmode(MODE)\sfunction\sin\sthe\sfileio.c\sextension\sand\suse\sthat\sfunction\nin\sthe\s.archive\simplementation.\s\sAdd\sthe\s--append\sand\s--dryrun\soptions\sto\nthe\s.archive\scommand\sand\sremove\sthe\s--zip\soption,\smaking\sit\sautomatic.
++D 2018-01-10T17:44:03.548
  F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
  F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
  F Makefile.in 12b6daa4bdb03fa87da27cbc205ff88ace645475b5be79414a3038b68ade14cb
@@@ -1697,7 -1697,7 +1697,8 @@@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a9
  F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
  F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
  F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
- P 94bc3c60e7d2ec849b90444b06e3057ed645edf3af334f2737252960602868e5
- R 9dfa6dcaeef4eb497b2c9753cb4a2823
- U dan
- Z 2990c2df8ab5dd5a7f9266ba3fc45276
 -P 52d12ba9f33c1f2620776e189c81f3bf991759344ecdd167ea2a6107f0972b9d
 -R 1170208662cbaecd416c0d66fbee2d48
++P 1f099b2b45074c89eeff8ff241aa49489c95c2221b25c305fcda670ebf63fb4e 612b30c95f948438016bd11470e9dd114d7bb064418a57e5954a094d2ca77f69
++R 92ad9119ea4a1b866aa95ac38fa72e64
++T +closed 612b30c95f948438016bd11470e9dd114d7bb064418a57e5954a094d2ca77f69
+ U drh
 -Z 6adbf06d453c4d240bb3d139f4f72e24
++Z 0e2d546e002bd2ff2da7a7782cc6fb79

diff --cc manifest.uuid
index b72ce7ac03988e470a77a8891db163f3f0c9962e,c546e6b5ffeb632b57baeb824f6227ef043bcaa3..cc72e08c3d96c41822cc6569500181c7efd6693e
--- 1/manifest.uuid
--- 2/manifest.uuid
+++ b/manifest.uuid
@@@ -1,1 -1,1 +1,1 @@@
- 1f099b2b45074c89eeff8ff241aa49489c95c2221b25c305fcda670ebf63fb4e
 -612b30c95f948438016bd11470e9dd114d7bb064418a57e5954a094d2ca77f69
++38f28029d16df8489772c27867de8888dd1c26b170861acdc977fd4023939dde