Fix line_graph_intuition in IE

Apparently this exercise has been broken in IE for a while :(

We weren't correctly detecting whether we were reprocessing the same graphie element a second time which caused invalid code to be executed and javascript processing to stop, making the find-slope-and-yint problem type unanswerable.

fix #113766; fix #113653; fix #113620; fix #113546; fix #113085; fix #113045;
fix #112973; fix #112560; fix #112497; fix #112142; fix #112040; fix #111914;
fix #111911; fix #111862; fix #111691; fix #110992; fix #110673; fix #110604;
fix #110571; fix #110548; fix #110520; fix #110439; fix #110272; fix #110245;
fix #109918; fix #109754; fix #109564; fix #109513; fix #109084; fix #109077;
fix #108741; fix #108714; fix #108710; fix #107965; fix #107852; fix #107687;
fix #107686; fix #107664; fix #107648; fix #107506; fix #107497; fix #107492;
fix #107482; fix #107437; fix #107288; fix #107279; fix #107246; fix #107173;
fix #107161; fix #107151; fix #107148; fix #107130; fix #107112; fix #107111;
fix #107103; fix #107073; fix #107071; fix #107063; fix #107054; fix #107053;
fix #107047; fix #107037; fix #107028; fix #107027; fix #107014; fix #107012;
fix #106983; fix #106982; fix #106960; fix #106942; fix #106939; fix #106938;
fix #106937; fix #106932; fix #106925; fix #106899; fix #106885; fix #106877;
fix #106830; fix #106790; fix #106759; fix #106755; fix #106710; fix #106703;
fix #106701; fix #106689; fix #106687; fix #106681; fix #106676; fix #106628;
fix #106615; fix #106603; fix #106602; fix #106583; fix #106553; fix #106549;
fix #106544; fix #106482; fix #106453; fix #106412; fix #106408; fix #106332;
fix #106306; fix #106259; fix #106222; fix #106210; fix #106170; fix #106148;
fix #106134; fix #106095; fix #106087; fix #106076; fix #106075; fix #106053;
fix #106045; fix #106027; fix #106020; fix #106005; fix #105943; fix #105929;
fix #105920; fix #105918; fix #105909; fix #105906; fix #105895; fix #105894;
fix #105889; fix #105855; fix #105849; fix #105804; fix #105803; fix #105781;
fix #105775; fix #105771; fix #105769; fix #105768; fix #105765; fix #105749;
fix #105724; fix #105702; fix #105684; fix #105683; fix #105671; fix #105658;
fix #105653; fix #105629; fix #105602; fix #105600; fix #105595; fix #105583;
fix #105581; fix #105575; fix #105573; fix #105571; fix #105556; fix #105550;
fix #105488; fix #105460; fix #105456; fix #105446; fix #105423; fix #105398;
fix #105384; fix #105278; fix #105271; fix #105232; fix #105228; fix #105203;
fix #105115; fix #105044; fix #105008; fix #105005; fix #104932; fix #104899;
fix #104897; fix #104880; fix #104861; fix #104835; fix #104834; fix #104833;
fix #104832; fix #104830; fix #104745; fix #104740; fix #104733; fix #104690;
fix #104678; fix #104676; fix #104646; fix #104580; fix #104574; fix #104553;
fix #104514; fix #104505; fix #104495; fix #104493; fix #104484; fix #104477;
fix #104424; fix #104357; fix #104335; fix #104334; fix #104317; fix #104296;
fix #104291; fix #104283; fix #104282; fix #104269; fix #104254; fix #104164;
fix #104121; fix #104120; fix #104116; fix #104114; fix #104106; fix #104041;
fix #104032; fix #104027; fix #104020; fix #103969; fix #103939; fix #103905;
fix #103902; fix #103888; fix #103878; fix #103877; fix #103866; fix #103858;
fix #103792; fix #103787; fix #103783; fix #103777; fix #103773; fix #103745;
fix #103714; fix #103675; fix #103585; fix #103569; fix #103534; fix #103498;
fix #103486; fix #103460; fix #103434; fix #103426; fix #103425; fix #103369;
fix #103332; fix #103324; fix #103317; fix #103292; fix #103279; fix #103236;
fix #103229; fix #103225; fix #103215; fix #103209; fix #103201; fix #103200;
fix #103179; fix #103173; fix #103160; fix #103149; fix #103137; fix #103128;
fix #103127; fix #103085; fix #103067; fix #103020; fix #103017; fix #103014;
fix #103007; fix #102987; fix #102979; fix #102978; fix #102977; fix #102970;
fix #102953; fix #102952; fix #102932; fix #102902; fix #102895; fix #102857;
fix #102852; fix #102796; fix #102786; fix #102736; fix #102724; fix #102665;
fix #102664; fix #102577; fix #102467; fix #102434; fix #102386; fix #102317;
fix #102300; fix #102206; fix #101898; fix #101863; fix #101846; fix #101695;
fix #101616; fix #101510; fix #101342; fix #101323; fix #101314; fix #101313;
fix #101311; fix #101309; fix #101307; fix #101291; fix #101246; fix #101244;
fix #101179; fix #101152; fix #101118; fix #101102; fix #101095; fix #101063;
fix #101032; fix #100965; fix #100842; fix #100816; fix #100762; fix #100760;
fix #100740; fix #100696; fix #100683; fix #100673; fix #100656; fix #100648;
fix #100642; fix #100558; fix #100557; fix #100516; fix #100496; fix #100476;
fix #100469; fix #100468; fix #100453; fix #100429; fix #100416; fix #100401;
fix #100387; fix #100381; fix #100365; fix #100363; fix #100352; fix #100256;
fix #100246; fix #100234; fix #100231; fix #100226; fix #100225; fix #100217;
fix #100202; fix #100158; fix #100154; fix #100146; fix #100138; fix #100108;
fix #100085; fix #100084; fix #100075; fix #100032; fix #99955; fix #99911;
fix #99904; fix #99773; fix #99768; fix #99713; fix #99668; fix #99649;
fix #99648; fix #99622; fix #99604; fix #99602; fix #99484; fix #99465;
fix #99374; fix #99343; fix #99340; fix #99332; fix #99305; fix #99112;
fix #99110; fix #99097; fix #99096; fix #99090; fix #99082; fix #99077;
fix #99020; fix #99000; fix #98977; fix #98866; fix #98841; fix #98834;
fix #98789; fix #98758; fix #98746; fix #98711; fix #98698; fix #98637;
fix #98582; fix #98538; fix #98532; fix #98497; fix #98462; fix #98405;
fix #98353; fix #98294; fix #98226; fix #98096; fix #98081; fix #98070;
fix #97970; fix #97742; fix #97652; fix #96980; fix #96875; fix #94115;
fix #93563; fix #93282; fix #92848; fix #92809; fix #92564; fix #92499;
fix #92427; fix #92425; fix #92129; fix #41888

Test Plan: Locally test the find-slope-and-yint problem type from line_graph_intuition in IE8 and chrome.

Auditors: alex