Fix incomplete abstract and title

Closes gijswobben#23

In some cases the title and/or abstract obtained was incomplete.

Example: PMID 31689885
TItle tag:
<ArticleTitle>Gamma Irradiated <i>Rhodiola sachalinensis</i> Extract Ameliorates [...]</ArticleTitle>
Result was: 'Gamma Irradiated ' (now is 'Gamma Irradiate Rhodiola sachalinensis Extract[...]')
<AbstractText>The effect of <i>Rhodiola sachalinensis</i> Boriss extract irradiated [...]</ArticleTitle>
Result was: 'The effect of '

Solution: cleanup of html markup tags such as <i>, <sub>, <sup>.

pymed/api.py

@@ -1,4 +1,5 @@
 import datetime
+import re
 import requests
 import itertools
 
@@ -170,6 +171,9 @@ def _getArticles(self: object, article_ids: list) -> list:
             url="/entrez/eutils/efetch.fcgi", parameters=parameters, output="xml"
         )
 
+        # Remove html markup tags (<i>, <sub>, <sup>) to prevent text truncation
+        response = re.sub("</?i>|</?su[bp]>", "", response)
+
         # Parse as XML
         root = xml.fromstring(response)