Added Aqualoc dataset example for monocular SLAM

[olayasturias]

Added monocular example for Aqualoc dataset.
Two new files have been included:

1. mono_acualoc.cc, which loads the images and the associated timestamps
2. Aqualoc.yaml, with the camera parameters for aqualoc

The CMakeLists has also been updated accordingly.

The usage, as indicated by the script, is as follows:

./mono_aqualoc path_to_vocabulary path_to_settings path_to_sequence number_of_seq

For example (if run from the Examples folder):

./Monocular/mono_aqualoc ../Vocabulary/ORBvoc.txt Monocular/Aqualoc.yaml /path/to/Aqualoc/Archaeological_site_sequences/archaeo_sequence_1\_raw_data 1