Calculate out which context has the minum coverage thusfar.

    :param context_type: 'target' or 'query'
    :type context_type: string
    :returns: Minimum Coverage
    :rtype: int

def get_min_context_count(self,context_type):
    """Calculate out which context has the minum coverage thusfar.

    :param context_type: 'target' or 'query'
    :type context_type: string
    :returns: Minimum Coverage
    :rtype: int

    """
    cnt = 10000000000
    bases = ['A','C','G','T']
    basesplus = ['A','C','G','T','-']
    r = None
    if context_type == 'target':
      r = self.get_target_context_errors()
    elif context_type == 'query':
      r = self.get_query_context_errors()
    else:
      sys.stderr.write("ERROR incorrect context type\n")
      sys.exit()
    for b1 in bases:
      for b2 in bases:
        for b3 in basesplus:
          if r[b1][b2][b3]['total'] < cnt: cnt = r[b1][b2][b3]['total']
    return cnt