Polish mobile doc

.gitmodules

@@ -7,3 +7,6 @@
 [submodule "anakin"]
 	path = anakin
 	url = https://github.com/PaddlePaddle/Anakin.git
+[submodule "mobile"]
+	path = mobile
+	url = https://github.com/PaddlePaddle/paddle-mobile.git

mobile @ c3aa92ac

+Subproject commit c3aa92ac28662d7a1553cd258ddd3f19412f5018

source/advanced_usage/deploy/images

+../../../mobile/doc/images/
\ No newline at end of file

source/advanced_usage/deploy/index.rst

@@ -40,4 +40,6 @@
 .. toctree::
    :maxdepth: 2
 
-   mobile_readme.md
+   mobile_build.md
+   mobile_design.md
+   mobile_dev.md

source/advanced_usage/deploy/mobile_build.md

+../../../mobile/doc/build.md
\ No newline at end of file

source/advanced_usage/deploy/mobile_design.md

+../../../mobile/doc/design_doc.md
\ No newline at end of file

source/advanced_usage/deploy/mobile_dev.md

+../../../mobile/doc/development_doc.md
\ No newline at end of file

source/advanced_usage/deploy/mobile_readme.md

-../../../mobile/README.cn.md
\ No newline at end of file