Added concrete example to Quickstart section.

README.rst

@@ -82,6 +82,37 @@ Import `nmrstarlib` library and create generator function that will yield
    ...     print(starfile.source)         # print source of StarFile
    ...     print(list(starfile.keys()))   # print StarFile saveframe categories
    >>>
+   >>> # For example, let's read two files: one using BMRB id and the other one using URL:
+   >>> starfile_gen = nmrstarlib.read_files("15000", "http://rest.bmrb.wisc.edu/bmrb/NMR-STAR3/18569")
+   >>>
+   >>> for starfile in starfile_gen:
+   ...     print("BMRB id:", starfile.bmrbid)
+   ...     print("Source:", starfile.source)
+   ...     print("List of saveframes and comments:", list(starfile.keys()))
+   BMRB id: 15000
+   Source: http://rest.bmrb.wisc.edu/bmrb/NMR-STAR3/15000
+   List of saveframes and comments: ['data', 'comment_0', 'save_entry_information', 'comment_1',
+   'save_citation_1', 'comment_2', 'save_assembly', 'comment_3', 'save_F5-Phe-cVHP', 'comment_4',
+   'save_natural_source', 'comment_5', 'save_experimental_source', 'comment_6','save_chem_comp_PHF',
+   'comment_7', 'comment_8', 'save_unlabeled_sample', 'save_selectively_labeled_sample',
+   'comment_9', 'save_sample_conditions', 'comment_10', 'save_NMRPipe', 'save_PIPP', 'save_SPARKY',
+   'save_CYANA', 'save_X-PLOR_NIH', 'comment_11', 'comment_12', 'save_spectrometer_1',
+   'save_spectrometer_2', 'save_spectrometer_3', 'save_spectrometer_4', 'save_spectrometer_5',
+   'save_spectrometer_6', 'save_NMR_spectrometer_list', 'comment_13', 'save_experiment_list',
+   'comment_14', 'comment_15', 'comment_16', 'save_chemical_shift_reference_1', 'comment_17',
+   'comment_18', 'save_assigned_chem_shift_list_1']
+   BMRB id: 18569
+   Source: http://rest.bmrb.wisc.edu/bmrb/NMR-STAR3/18569
+   List of saveframes and comments: ['data', 'comment_0', 'save_entry_information', 'comment_1',
+   'save_entry_citation', 'comment_2', 'save_assembly', 'comment_3', 'save_EVH1', 'comment_4',
+   'save_natural_source', 'comment_5', 'save_experimental_source', 'comment_6', 'comment_7',
+   'save_sample_1', 'save_sample_2', 'save_sample_3', 'save_sample_4', 'comment_8',
+   'save_sample_conditions_1', 'save_sample_conditions_2', 'save_sample_conditions_3',
+   'save_sample_conditions_4', 'comment_9', 'save_AZARA', 'save_xwinnmr', 'save_ANSIG',
+   'save_CNS', 'comment_10', 'comment_11', 'save_spectrometer_1', 'save_spectrometer_2',
+   'save_NMR_spectrometer_list', 'comment_12', 'save_experiment_list', 'comment_13',
+   'comment_14', 'comment_15', 'save_chemical_shift_reference_1', 'comment_16', 'comment_17',
+   'save_assigned_chem_shift_list_1', 'comment_18', 'save_combined_NOESY_peak_list']
 
 .. note:: Read `User Guide`_ and `The nmrstarlib Tutorial`_ on ReadTheDocs_ to learn more and see code examples on using
           `nmrstarlib` as a library and as a command-line tool.