Update instructions to use rosinstall_generator and fix minor typos
Add function to get topic type
Update definition method of BagInfo
  -Remove rawDefintion function and set flag inside defintion
  -Check if input is a topic or msg type
Add function that returns all topics in bag
Add support for regular expression matching of topic names
Improve compilation instructions

- Remove a few small typos
- Use install targets for boost and ros libraries
Remove read_bag_test
Return cell array of strings when appropriate

- If a field's type is an array of strings, the Matlab field should be a
  cell array, even when there's one element (rosbag_wrapper.cpp)
- When getting topics in a bag, user should get cell array even when
  there's only one topic (matlab_util.hpp)