Update versionName to 0.1.1 in manifest file

This is a hotfix branch aiming at adding Javadoc to the source code.
Update versionCode to 2 in manifest file

The rule to assign versionCode in AndroidManifest.xml file:
The first release on master branch has a versionCode of integer 1.
Every release on master branch will increase the versionCode by one.
Update version number to 0.1.1 in about activity

Change happens in strings_activity_about.xml.
Update version number in LICENSES file
Update version number to 0.1.1 in README.md
Fix ENOTDIR error

This is really weird, because I thought I've already fixed it before.
But it turns out the solution still has flaws. But this time I don't
think there's any problem with the EpubFileProcessor any more.

The problem exists in unzipEpubFile method of EpubFileProcessor.
Sometimes when it starts to unzip the cantainer.xml file, the error
ENOTDIR may occur, I think maybe this has something to do with the
compression algorithm the epub file uses. Because sometimes it seems
that the META-INF directory doesn't exist before META-INF/container.xml
file. So when unzipping the xml file, the error occurs. To solve this,
just make directories leading up the xml file before open it and write
to it.
Fix ENOTDIR error when unzipping META-INF/container.xml

* hotfix-0.1.1:
  Fix ENOTDIR error
  Update version number to 0.1.1 in README.md
  Update version number in LICENSES file
  Update version number to 0.1.1 in about activity
  Update versionCode to 2 in manifest file
  Update versionName to 0.1.1 in manifest file