read_xmile issue with equations over multiple lines

[peterhovmand]

read_xmile doesn't seem to work with XMILE equations that span multiple lines. For example, Stella allows line breaks in equations to make equations more readable. These are exported to XMILE by separating the equations to multiple lines. For example, the following equation in XMILE generates an error:

<eqn>Ethnic_Identity/
    REF_Ethnic_Identity</eqn>