Add the ".once -e" and ".once -x" commands to the CLI, and the ".excel" command

that is an alias for ".once -x".

FossilOrigin-Name: a6ed5ab9bc9741267fd1207e63b4c49d074291085c7e3f25e9f62a82f916a656

diff --cc manifest
index 63c68f6f7e843e6f30bdcdbb33bd37fb3a194353,4766b6496ad940c807ea2623bf1cb6544dccf6e9..18f1e54d50bc774c979b1c145d39dadba8d284e2
--- 1/manifest
--- 2/manifest
+++ b/manifest
@@@ -1,5 -1,5 +1,5 @@@
- C Fix\sa\sharmless\scompiler\swarning\sin\szipfile.c
- D 2018-01-10T19:50:40.811
 -C Update\stest\scases\sfor\sthe\snew\s"usage"\sfor\s.output.
 -D 2018-01-10T23:27:30.001
++C Add\sthe\s".once\s-e"\sand\s".once\s-x"\scommands\sto\sthe\sCLI,\sand\sthe\s".excel"\scommand\nthat\sis\san\salias\sfor\s".once\s-x".
++D 2018-01-10T23:29:42.447
  F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
  F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
  F Makefile.in 38f84f301cbef443b2d269f67a74b8cc536469831f70df7c3e912acc04932cc2
@@@ -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 6a6a3d495633b906ca31f513c30d31e6daf0f0f105be9ba0a0dc07d201d5b630
- R 47ef8e39d746f78565d92ddee819e4f1
 -P f697c164518d36f2a63c87d9f2708d0f9481fad3ded2de61f3f48c393cf7a500
++P 60c694c1ab26a7a096f17ccea5a93ecda0f9f2113ab5fdc8b17dbffc787724fc fbf5e43c07e7c012cb39b33a74b3fab9e46ba946c48497fbd990110692125f57
+ R cbc8182064251451cd032585a1a8098f
++T +closed fbf5e43c07e7c012cb39b33a74b3fab9e46ba946c48497fbd990110692125f57
  U drh
- Z 8e9572c27b3beeb784a18b126ea860dc
 -Z 0fca8af732176ea4c3e2417e5169029d
++Z c9d5887fceb0e0e24e4f6ea11d33b5eb

diff --cc manifest.uuid
index 12625a7794f3473e9169142cb5dea40c68dd7dfe,6ef1621db8298d6de71a696e5a0f78a73db403f5..ff97541f24744e2ebe7c0ef76fb53ea5f1f6ef2c
--- 1/manifest.uuid
--- 2/manifest.uuid
+++ b/manifest.uuid
@@@ -1,1 -1,1 +1,1 @@@
- 60c694c1ab26a7a096f17ccea5a93ecda0f9f2113ab5fdc8b17dbffc787724fc
 -fbf5e43c07e7c012cb39b33a74b3fab9e46ba946c48497fbd990110692125f57
++a6ed5ab9bc9741267fd1207e63b4c49d074291085c7e3f25e9f62a82f916a656