Store intermediate results as metadata to improve speed and debug

Metadata for images contain:
img_params, A_img_params, imgtrack
Metadata for scans contain:
scantrack, inPts and lost

Changes in loadCamData.m:
- Now receives optional 'indexs' input to choose the span of image indexes for calibration, if no input is given uigetfile will pop up for manual selection
- Images are not loaded all at once, so field Im is kept empty for later loading
- Added fields path (full path to image, for later loading) and metafile (full path to metadata file)

Changes in loadDataSet.m:
- Array of scans is filtered so that only closest scan to each image is kept
- Field delta_ts is kept to check how good pair is

Changes in loadLidarData.m:
- Added field metafile

Change in main.ini:
- WITH_MONTECARLO is a external variable
- VIDEO_PREVIEW is deprecated
- Added img_idxs to select input images

Changes in main.m:
- If metadata exists for current image or scan it is loaded instead of computing tracking

Changes to help text in readConfigFile
In optimRotation.m:
- Added function to compute R differential wrt n and l
- Added R covariance estimation for non-weighted optimization
- Added Monte Carlo simulation for checking covariance

In precondwithErrFun.m:
- Changed threshold (TODO: Explore best values)
- Added A_eps for Monte Carlo in rot_input

In main.m:
- Updated optimRotation call
- Results are stored now in .ini-like files

In spaceOps.m:
- Changed spaces format: Now each space is coded as a struct with fields 'topo' and 'dim' for easing the use of different topological spaces with all possible dimensions

New functions:
- manDiffRotExp and manDiffRotLog for exp and log maps differential
- saveConfigFile saves the fields in a struct in a .ini-like file