libjpeg API: Partial scanline decompression

This, in combination with the existing jpeg_skip_scanlines() function,
provides the ability to crop the image both horizontally and vertically
while decompressing (certain restrictions apply-- see libjpeg.txt.)

This also cleans up the documentation of the line skipping feature and
removes the "strip decompression" feature from djpeg, since the new
cropping feature is a superset of it.

Refer to #34 for discussion.

Closes #34

Cherry picked from upstream:
https://github.com/libjpeg-turbo/libjpeg-turbo/commit/3ab68cf563f6edc2608c085f5c8b2d5d5c61157e

BUG:27290496

Change-Id: Id11312fa43959531bc6bea04ebb657c6e1140363
diff --git a/README.android b/README.android
index b83c4d7..6d0c087 100644
--- a/README.android
+++ b/README.android
@@ -13,15 +13,7 @@
 (2) Partial decoding optimizations
 
 These have been cherry picked from upstream and will be included in the 1.5
-release.  The cherry picked commits are:
-90c92ed5bf98bda381fcc369f0da46837dbb8894
-fc235cfdabbcd1c915fa3a87a56d73727da2eaeb
-9bafc6a7ffa62ed7109314cbb66085075cd1c334
-3fb56e969c890e6aa7b044eea7e24751ab6f4e97
-e67a7e37deb26db5ac7da420560d22e1ca7ea4b4
-f8a1775eab51fb0a83e82343d2eae8cf52b16124
-15884f48eb1a4acd9c6c24291db974c596e71934
-ac30a1bf12751bd82e56158eb9456a28d9c086f3
+release.
 
 (3) simd/jsimdext.inc