Add specs to test against source patterns

[ronaldtse]

Add specs to test against parsing "source" and "clause" from #9:

Add these cases to term_workbook_spec.rb:

    "ISO 1087-1:2000, 3.4.15",
    "ISO/TS 19130:2010",
    "ISO/IEC Guide 99:2007, 2.15",
    "ISO/IEC 10746-2",
    "ISO/IEC 19501:2005 (Adapted from)",
    "ISO 19108;2002",
    "ISO/IEC TR 10000-1:1998",
    "ISO 10241-1:2011, 3.4.2.3, modified — The reference to the examples has been removed.",
    "ISO 19103:2015, modified – Derived from 7.5.2.1",
    "ISO/TS 19159-2:2016, 4.1",
    "ISO 19146:2010, 4.9, modified — In the definition, the words terminological record have been changed to terminological entry.",
    "ISO 19111:2007, 4.22, modified – The first occurrence of the words “semi-major” have been expanded to “semi-major axis”.",
    "ISO 19111:2007, 4.22, modificado – la primera ocurrencia de las palabras \"semi-mayor\" se han ampliado a \"semieje mayor\"",
    "ISO/IEC 11179-3:2003(Adapted from)",
    "ISO 2859‑5:2005, 3.4, modified – Original Example has been removed. Note 1 to entry has been added."