Fixes for snapshots API on this branch. Also ensure that the snapshots API

cannot be used with wal2 mode databases (for now anyhow).

FossilOrigin-Name: d8c2d55fa4ec95c6506201edcd1cb2ef108a233bd87a6154f3593909977f7d3f

diff --cc manifest
index dc2ae521ba52baa347010f77cf139532ae097fce,5cf7e8b10d7dfa323a8181de53626fab37089918..965f4e37e1fea693e4cad4f7fab9ac18cace3df5
--- 1/manifest
--- 2/manifest
+++ b/manifest
@@@ -1,5 -1,5 +1,5 @@@
- C First\sattempt\sat\smaking\sfeatures\swork\stogether.\sOnly\sthe\smost\sminimal\stesting\nso\sfar.
- D 2018-12-04T19:41:07.389
+ C Fixes\sfor\ssnapshots\sAPI\son\sthis\sbranch.\sAlso\sensure\sthat\sthe\ssnapshots\sAPI\ncannot\sbe\sused\swith\swal2\smode\sdatabases\s(for\snow\sanyhow).
 -D 2018-12-05T16:31:02.698
++D 2018-12-05T16:45:38.015
  F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
  F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
  F Makefile.in a050c8670ea0d7b37b2192306cbb50d392acd9902b84e9b56f3444d006f97a6c
@@@ -593,8 -589,8 +593,8 @@@ F src/vdbesort.c 90aad5a92608f2dd771c96
  F src/vdbetrace.c 79d6dbbc479267b255a7de8080eee6e729928a0ef93ed9b0bfa5618875b48392
  F src/vtab.c 70188a745dc4e57d26e942681ff4b2912b7c8249ad5de3f60f0677b4337bcfaa
  F src/vxworks.h d2988f4e5a61a4dfe82c6524dd3d6e4f2ce3cdb9
- F src/wal.c 4b7ad0e623e01ede1ecb2cae24548c29e51ce5a21b2fd91af26b4bb447b72cc4
 -F src/wal.c 2b9b1bc7eeb819b46b0abe0bf4d9c48a13df0989814bb213da1b480d4b1c8107
 -F src/wal.h fc6113057f2950fc14631176b748293e216fb385ea8df665e6d259e37f8f7d21
++F src/wal.c 171d066ccb727aeb439d14fbe1b91a488f2efd9fcdb5d3d245f6120d575d6c5f
 +F src/wal.h b42fc8081cd1765d4d4dd99b33f2db2f71128f4e25ff8c08d1a346f5af62e27a
  F src/walker.c fb94aadc9099ff9c6506d0a8b88d51266005bcaa265403f3d7caf732a562eb66
  F src/where.c 3818e8a736a05d2cb194e64399af707e367fbcc5c251d785804d02eaf121288e
  F src/whereInt.h f125f29fca80890768e0b2caa14f95db74b2dacd3a122a168f97aa7b64d6968f
@@@ -1796,7 -1782,7 +1796,7 @@@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a9
  F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
  F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
  F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
- P b7281a1caa574870a071bea3e96b1d8210c28c17f9094449b3ce1a42b311e6a1
- R db024f31bd5bbdadf08ded59e2f54e6f
 -P 480be916c840e9e28010c22cf29a8396502c9e6387f31f750260c6290f58e9a1
 -R 869a87f8972d12d94814188a57f87377
++P fd707001f0afb1cf32cfeeda3ec7b5622eb49ddedf8fec1a7aa4c8841c77c37a 19c61ab79458936ff4dfca46cf4d1fb1ab16d7bdb5024f502eb4339ec4eef32c
++R 09f6147c8a217ef98a62e556b947a346
  U dan
- Z abc3921392e51c645845b41c65979599
 -Z 200899075d870fbfb9b7c809d447f2d7
++Z 846b44a376c01a8515808ab90c59f028

diff --cc manifest.uuid
index e66f70d089cb7295c5df6dc10e0afd17377b4bf1,0754a48ec21ee984f424c9557fdb913bcccc22c5..b72d33ac55ea7c716ec202261fd4ac703ae62154
--- 1/manifest.uuid
--- 2/manifest.uuid
+++ b/manifest.uuid
@@@ -1,1 -1,1 +1,1 @@@
- fd707001f0afb1cf32cfeeda3ec7b5622eb49ddedf8fec1a7aa4c8841c77c37a
 -19c61ab79458936ff4dfca46cf4d1fb1ab16d7bdb5024f502eb4339ec4eef32c
++d8c2d55fa4ec95c6506201edcd1cb2ef108a233bd87a6154f3593909977f7d3f

diff --cc src/wal.c
Simple merge