fix #23; add OCR features (character-based TLM)

Compare BL and LR models:

Precision means:  0.782438635977 0.959594697662
Recall    means:  0.731509330406 0.959009330406
F-scores  means:  0.743763317809 0.959091722877

Precision - Paired t-test: t=-268.587941868, p=1.50734753914e-143
Recall    - Paired t-test: t=-317.075923811, p=1.12423096316e-150
F-score   - Paired t-test: t=-316.415545073, p=1.3816819239e-150

Compare BL and DT models:

Precision means:  0.782438635977 0.921497785042
Recall    means:  0.731509330406 0.92108946213
F-scores  means:  0.743763317809 0.921121188376

Precision - Paired t-test: t=-203.530370422, p=1.20744535282e-131
Recall    - Paired t-test: t=-268.806269654, p=1.39099437884e-143
F-score   - Paired t-test: t=-259.702705227, p=4.19350440624e-142

Compare BL and SVM models:

Precision means:  0.782438635977 0.930018144482
Recall    means:  0.731509330406 0.927198133919
F-scores  means:  0.743763317809 0.927729281218

Precision - Paired t-test: t=-202.65624838, p=1.84706417023e-131
Recall    - Paired t-test: t=-244.593389362, p=1.56945267793e-139
F-score   - Paired t-test: t=-240.169097069, p=9.53393488933e-139

Compare LR and DT models:

Precision means:  0.959594697662 0.921497785042
Recall    means:  0.959009330406 0.92108946213
F-scores  means:  0.959091722877 0.921121188376

Precision - Paired t-test: t=66.8471368983, p=3.44632018154e-84
Recall    - Paired t-test: t=66.4238532054, p=6.37637378644e-84
F-score   - Paired t-test: t=66.4833675023, p=5.84661164603e-84

Compare LR and SVM models:

Precision means:  0.959594697662 0.930018144482
Recall    means:  0.959009330406 0.927198133919
F-scores  means:  0.959091722877 0.927729281218

Precision - Paired t-test: t=59.026914686, p=5.71022132992e-79
Recall    - Paired t-test: t=60.477829946, p=5.50154162893e-80
F-score   - Paired t-test: t=60.1689403938, p=9.01302972185e-80

Compare DT and SVM models:

Precision means:  0.921497785042 0.930018144482
Recall    means:  0.92108946213 0.927198133919
F-scores  means:  0.921121188376 0.927729281218

Precision - Paired t-test: t=-14.861928988, p=5.87249474255e-27
Recall    - Paired t-test: t=-10.452341484, p=1.13012609307e-17
F-score   - Paired t-test: t=-11.338021052, p=1.3562697844e-19