Improvements to PRAGMA integrity_check.

Verify CHECK constraints.
Verify NOT NULL constraints even on table that lack indexes.
Verify CHECK and NOT NULL constraints with PRAGMA quick_check.

FossilOrigin-Name: aa02bd3c95e374008b930d296c88dfafaf11c65a

diff --cc manifest
index 0c80aaffbabeb4f4bdf404b23f3315152732804b,677bc6001d5c53efe1d7b1c88b170441ed86377f..061f9eb07e9ff0683593b83eece7216c3ae30248
--- 1/manifest
--- 2/manifest
+++ b/manifest
@@@ -1,5 -1,5 +1,5 @@@
- C In\ssqlite3VdbeHalt(),\sreturn\sas\ssoon\sas\spossible\sif\nVdbe.magic!=VDBE_MAGIC_RUN.\sThis\smakes\ssqlite3_reset()\sslightly\sfaster\sin\ssome\ncases.
- D 2017-02-21T21:24:05.029
 -C Cleanup\sand\ssimplification\sof\sthe\soutput\srow\scount\slimit\scontrol\sof\nPRAGMA\sintegrity_check.
 -D 2017-02-22T18:04:42.473
++C Improvements\sto\sPRAGMA\sintegrity_check.\nVerify\sCHECK\sconstraints.\nVerify\sNOT\sNULL\sconstraints\seven\son\stable\sthat\slack\sindexes.\nVerify\sCHECK\sand\sNOT\sNULL\sconstraints\swith\sPRAGMA\squick_check.
++D 2017-02-22T18:53:13.913
  F Makefile.in edb6bcdd37748d2b1c3422ff727c748df7ffe918
  F Makefile.linux-gcc 7bc79876b875010e8c8f9502eb935ca92aa3c434
  F Makefile.msc a89ea37ab5928026001569f056973b9059492fe2
@@@ -1557,7 -1557,7 +1557,7 @@@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a9
  F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
  F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
  F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
- P e400909f313c317b7b67be6eb867ed61df7383dc
- R 5434ea5a08220297aa4d56dd68f46447
- U dan
- Z 68cf5c57f26344b5e30f88013a5c9e52
 -P 5264844b069cdc20f456acee9f5b2b97c986120d
++P 80adc0cb4ed7bacc54b15ac8b5b205403939c8c4 5af7d72ed9ec758283d78ceb46627d72021c1c60
+ R 46f90a15a015e3c65c6378dae6f8ff19
+ U drh
 -Z ac3f9bd06db21fa3e22e700d592b007d
++Z 9fac49478b578adef606b235c8c223db

diff --cc manifest.uuid
index 2ace79cb168bb24514c612bdd1ae6057042c9397,de6e14387f9ec4b178cafd5057515af9889fbfa7..f457c0397dbff0b62c2e1764bf5ad86430193f53
--- 1/manifest.uuid
--- 2/manifest.uuid
+++ b/manifest.uuid
@@@ -1,1 -1,1 +1,1 @@@
- 80adc0cb4ed7bacc54b15ac8b5b205403939c8c4
 -5af7d72ed9ec758283d78ceb46627d72021c1c60
++aa02bd3c95e374008b930d296c88dfafaf11c65a