Enhance the built-in date/time functions so that they can be used in

CHECK constraints, in the WHERE clause or partial indexes, and index
expressions, provided that none of the non-deterministic keywords
("now", "localtime", "utc") are used as arguments.

FossilOrigin-Name: a90c062d46c63a1e6f83064b1c5afb26a16e93b6ee8620ca46d169fdb325c488

diff --cc manifest
index c7ea2677a29544caa6f977c4ae2910e2697f607e,5ce4964e92f0ba18ff279213040d0c19314d804c..4932481eb6242cc8cb5f73d4faac646020bc30ba
--- 1/manifest
--- 2/manifest
+++ b/manifest
@@@ -1,5 -1,5 +1,5 @@@
- C Remove\ssome\s'breakpoint'\scommands\sin\stest\sfiles.
- D 2017-07-19T18:01:42.362
 -C New\stest\scases\sfor\sdate/time\sfunctions\sin\sindexes\son\sexpressions,\sin\sthe\nWHERE\sclause\sof\spartial\sindexes,\sand\sin\sCHECK\sconstraints.
 -D 2017-07-20T14:36:26.145
++C Enhance\sthe\sbuilt-in\sdate/time\sfunctions\sso\sthat\sthey\scan\sbe\sused\sin\nCHECK\sconstraints,\sin\sthe\sWHERE\sclause\sor\spartial\sindexes,\sand\sindex\nexpressions,\sprovided\sthat\snone\sof\sthe\snon-deterministic\skeywords\n("now",\s"localtime",\s"utc")\sare\sused\sas\sarguments.
++D 2017-07-20T15:08:43.378
  F Makefile.in d9873c9925917cca9990ee24be17eb9613a668012c85a343aef7e5536ae266e8
  F Makefile.linux-gcc 7bc79876b875010e8c8f9502eb935ca92aa3c434
  F Makefile.msc 02b469e9dcd5b7ee63fc1fb05babc174260ee4cfa4e0ef2e48c3c6801567a016
@@@ -1636,7 -1637,7 +1637,8 @@@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a9
  F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
  F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
  F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
- P c93284cd65b6471bffc38696e14dc24a2170698faf566cf91b727ba272f88c25
- R 9a0e35c22d772f08ad350059e0e65c0d
- U mistachkin
- Z 3b6354332c6aa6dc358fe07c8de8d63d
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++P d14fc621e918915bbf8e04597eb238ea78dff3d9c5eb4402cb88692d00dbdfee b7f70c7fcabc10b8b3e62fe5ac68476cec23acaee037c7250ff70bca3f3ab541
+ R 636bb2618e46215e27cfa1dc613ec36a
++T +closed b7f70c7fcabc10b8b3e62fe5ac68476cec23acaee037c7250ff70bca3f3ab541
+ U drh
 -Z 9fcd2c9047a36a4760d07f2c77f0a563
++Z 8d21c041010891259262753e78bdd45f

diff --cc manifest.uuid
index ce0522a734f1434f007846375c31b79e8a826c95,7e0ceb0e6307cbb9c0a5d8da7997c1a7e44312e6..9f9976a1090f5717aeea19983e6995d5df6bb402
--- 1/manifest.uuid
--- 2/manifest.uuid
+++ b/manifest.uuid
@@@ -1,1 -1,1 +1,1 @@@
- d14fc621e918915bbf8e04597eb238ea78dff3d9c5eb4402cb88692d00dbdfee
 -b7f70c7fcabc10b8b3e62fe5ac68476cec23acaee037c7250ff70bca3f3ab541
++a90c062d46c63a1e6f83064b1c5afb26a16e93b6ee8620ca46d169fdb325c488