clean up axis type and tick placement UX

Author: nicolaskruchten

src/components/fields/Text.js

@@ -27,7 +27,7 @@ export class UnconnectedText extends Component {
 }
 
 UnconnectedText.propTypes = {
-  defaultValue: PropTypes.number,
+  defaultValue: PropTypes.string,
   fullValue: PropTypes.any,
   multiValued: PropTypes.bool,
   updatePlot: PropTypes.func,

src/default_panels/StyleAxesPanel.js

@@ -276,7 +276,7 @@ class StyleAxesPanel extends Component {
             />
           </Section>
 
-          <Section name={_('Placement')} attr="dtick">
+          <Section name={_('Spacing')} attr="dtick">
             <Radio
               attr="tickmode"
               options={[
@@ -304,7 +304,7 @@ class StyleAxesPanel extends Component {
             <Numeric label={_('Width')} attr="tickwidth" units="px" />
             <ColorPicker label={_('Tick Color')} attr="tickcolor" />
           </Section>
-          <Section name={_('Placement')}>
+          <Section name={_('Spacing')}>
             <Radio
               attr="tickmode"
               options={[